Halloween is officially upon us on Grey's Anatomy. You can imagine the surprises destined to fall into the hands of the surgeons at Seattle Grace on this wacky holiday. Alex receives an unexpected visit from his former patient, while Meredith is convinced that her mother Ellis' ashes are haunting her, Cristina is snubbed by a surgeon she admires in Dr. Hahn, and Callie makes an announcement to her fellow doctors.
As the episode begins, Cristina is looking to rent out Burke’s apartment. She offers it to the Chief, who's officially been served with the divorce wishes from Adele. He accepts. Meredith for some reason decides that putting her mom’s ashes in a freezer bag and bringing them to work is a good idea. Izzie asks Callie a question and Callie tells her - and everyone else in the room - to please direct inquiries to Dr. Bailey as since Izzie is sleeping with her husband.

This episode promises not to disappoint.
Norman asks if he can go home because he's feeling under the weather. Alex doesn't care, and then learns that Ava - yes, Ava - is back.
She and Alex kiss in the on-call room. She reminds him he chickened out at the time she asked him for a reason to stay, but she's back because she wants to be with him. They have sex and fall asleep. Alex gets paged and tells Ava he'll be back so they can talk more about their situation.

He doesn't come back for a long time, though, because Norman had a stroke. When he finally comes back, Ava is gone. Alex apologizes to Norman for not answering his pages and for mocking him when he felt sick. Norman is going to switch his specialty to psychiatry, which is what he was leaning towards anyway, as surgeons are immature children. Which they are. But where's Ava? Will she return again?

Lexie Grey is wearing scrubs and a Little Bo Peep bonnet to work, in honor of Halloween, and gets criticized by the daughter of a patient who needs a heart transplant for not looking professional. The daughter is also wearing a costume - a mouse — but she doesn't cut people open for a living.

The daughter leaves, but is brought back later by paramedics when she is slammed by a brick. Really. She's still alive, but in a vegetative state. She's also an organ donor, with a heart her father could really use. Her father has the power to take her off of life support and have her organs donated... to himself, but he can't bring himself to.
George then makes a nice speech about how he's sure the daughter would have wanted him to take her heart because that's what he would have done with his own father. This convinces the man to take the transplant.

Richard invites Dr. Erica Hahn of Mercy West to perform the transplant, and Izzie and Cristina compete to be in on the surgery. Dr. Hahn picks Izzie because she calls Cristina out on her propensity to sleep with mentors.

This obviously doesn't go well with Yang, and she has it out with Izzie in the hallway. Cristina rips Izzie for sleeping with another woman's husband, and says that sleeping with Dr. Burke, who was her boyfriend and fiancé, was completely different. Izzie fires back that Cristina and Meredith are a closed circle, always excluding and judging her - and wasn't Derek married when he and Meredith first started sleeping together?

Miranda has a patient named James who claims his foot that doesn't belong to him. That's a new one. He says it feels like a corpse's, and wants her to amputate. When she suggests anti-anxiety medication, James who steals the chainsaw used for the pumpkin carving contest and tries to cut it off himself. You've gotta love Halloween.

Callie and Cristina do the amputation surgery - now necessary as the man has mangled his foot - and laugh at each other's relationship woes. Later, Cristina tells Dr. Hahn off, saying that she didn't sleep her way to the top and that it's Hahn who is being unprofessional.
That's when Richard announces that Eric Hahn is going to be joining Seattle Grace as the new head of cardiothoracic surgery. She's staying around! A flustered Cristina responds by immediately taking her apartment back from Richard. She gives it to Callie instead! Roommates!

Meredith crashes into Derek in the hallway, spilling some of her "bag of mommy"(ashes) on the floor. Derek says she is trying to deal and evolve.
A young boy, the son of a cafeteria worker, comes to ask for Mark, who is embroiled in his own problems right now as the nurses find out he's used the same lines to sleep with them all. They have unofficially formed a support group in Nurses United Against Mark Sloan. The kid, Ryan, is there to ask Mark for ears. He can hear but has no external ear structure.
Mark wants to help but won't do pro bono work. Meredith offers to use her mother and what's left of her "capital" to help convince others to help.
She succeeds and lines everything up. Mark tells her that even though her mother didn't take the time to take her trick-or-treating when she was a child, Meredith Grey still turned out alright. It's sweet.

Meredith, Cristina and ashes of Ellis are eating lunch as George and Izzie sit down to join. They confirm that they are together and in love, but they are waiting to be "together" out of respect for Callie. Cristina rolls her eyes with disgust at this, but Meredith tries to remain on even keel.

Later, Miranda is on the phone with her husband, apologizing for missing their son's first Halloween. Tucker hangs up on her. George joins her and apologizes for disappointing Bailey with his adultery, but she tells him he's not a bad person even though what he did was unkind and hurtful and wrong. She says that it takes two to reach that point.

After their surgeries, Lexie tells Meredith that she buried her mom's cat next to her because she thought Susan would have liked that. Meredith is just happy to have a friend at this moment and says thank you. Mer has a plan now. She washes the ashes down the sink in the scrub area outside of the OR. Richard joins her, and Ellis Grey is finally laid to rest in an appropriate manner for such an accomplished surgeon.

The long-awaited start to Season Four, "A Change is Gonna Come," promised not to disappoint, and it most certainly didn't. Just 17 days have passed since Cristina's wedding that wasn't. Today is the first day of being surgical residents for the fab four. Note that it's now the fab four. George, who must repeat his intern year because he failed his Step 3 exam, is now under the tutelage of Meredith.
Also, in an interesting twist, Lexie Grey, half-sister to Meredith, who memorably flirted with Derek at the bar in last season's finale, is Cristina's intern. It is also Callie's first day as chief resident, and it's pretty much the day from hell as Bailey is upset with the Chief for passing her over for that position, and extends her bitterness to Callie as well.
All hell breaks lose when a car accident sends victims into the hospital. All the residents get their interns together to meet the ambulances, and Lexie picks this hectic moment introduce herself as Mer's sister.
Derek, Meredith and Lexie later have an encounter in the hallway. Derek recognizes the younger Grey as the girl from the bar. The original Grey defiantly responds, “I'm the girl from the bar!”
Alex has a patient named Joey who seems alright, but is so hungry that he swipes cotton balls - and soon, other things - to eat. Alex and Callie are bickering so much that they don't notice this strange behavior, though.
Meredith's patient is a pregnant woman whose right arm was severed below the shoulder, cleanly from the crash. Cristina goes to call the time of death on another victim when he comes back to life. His head is cut off from his spinal cord and is only being held together by skin and muscle. Derek rushes to his aid.
George is having a hard time coming to grips with having to repeat his year as an intern, and there's clearly a lot else on his mind, as well. Callie tells him she might be pregnant and he's disinterested. There's also the matter of his avoiding Izzie, who has confessed her love to him.
Speaking of Izzie, she wasn't getting much love from her interns, who think she's crazy and a loser, at the start, and their impressions of her don't change when she decides to go all out to save a deer that had been hit in the accident. Really. A sad little boy talks her into it, begging Izzie to try to bring the (cute) animal back to life.
After researching everything she can online, Izzie tries to jump start its heart, and lo and behold - it works! She then says to her interns that take it or leave it, they're stuck with her and she is who she is. And maybe it's them who suck (in as many words).
Mark finds Derek and asks him if he wants to have a drink, since Derek is Meredith-less now. Derek defends her to Sloan, saying that she is damaged because her mother didn't want her and her father left her and her best friend was left at the altar, so of course she is wary.
After Alex's patient has eaten almost everything he can get his hands on, including clamps and scissors, Alex finally notices. He tells his interns to page Bailey. That doesn't sit well with Callie. Bailey realizes she's still in charge, no matter what her title says, a fact reinforced by the Chief telling her she belongs in the OR, not setting schedules, and that she'll thank him for this one day.
Mark is in the process of reattaching the pregnant lady's arm when she goes into labor. It happens so fast that there is no time to call an OB-GYN, so George jumps in to deliver the baby. Easily!
Derek's patient is not properly anesthetized and begins to move around on the table. Any movement at all could cause death, so the doctors scramble to increase anesthesia. Cristina tells him that he cannot move, that he told his family that he loves them so he cannot leave them. We know what Cristina is really referring to - missing Dr. Burke, who she learns from Derek is not coming back... ever.
George is outside of the nursery looking at the baby he delivered. Lexie joins him and is impressed to hear he delivered the baby on his first day as an intern. He bitterly tells her it's not is first day.
He goes into a big “What about me?” speech - despite saying he wouldn't do that - but a wise Lexie counters that she didn't want to come to Seattle, but her mom died and her father is a drunk, that Mer doesn't acknowledge her. So she tells George to stop feeling sorry for himself. He tells her she's kind of awesome.
Later, in the locker room, Lexie has spread the word that George delivered a baby on his very first day as an intern. She emphasizes that it was his VERY first day as an intern. He smiles as he tells them about it.
At the end of the day, in a rare moment of weakness for each, Alex and Cristina admit to each other they miss Ava and Burke, respectively. Dr. Bailey sees Callie sulking outside and offers her some cursory words.
Meredith and Derek go to an on-call room and decide that they have to break up. For real this time. Only they immediately share a passionate break up kiss, which leads to break up sex. Hot break up sex. So once again, we have no idea where it will lead!
Lastly, George shows up at Izzie's door and lets outs the three words she has been waiting 17 days to hear ... “I love you.”

An episode entitled “Didn’t We Almost Have It All” leaves a foreboding feeling in the air from the start. What will become of the race for Chief, the Chief's wife, the wedding, the intern in love with his patient and unwilling to admit it, the other intern in love with her married best friend, and the growing rift between Meredith and Derek? And there's the matter of the fourth rock climber with an ax lodged in his skull. We learn that this happened not because of an accident, as the trio of previously-admitted climbers originally tell the cops, but because he was badly hurt and suffering and one of them tried to kill him to put him out of his misery. Derek realized it was intentional during brain surgery on the man, and he confronted them until they caved.

With police and lawyers arriving on the scene, the man who wielded the axe defended his motives, saying he’d do it again if he had to. Derek is left wondering if he should be put out of his own misery, relationship-wise. After meetings with Addison, Mark and Preston in which he turns each down, Richard gives Derek the news that he's being recommended for the Chief of Surgery position. But Shepherd turns it down, telling Richard that there's a better man for the job - Richard. If he really wishes he could do it all over again, Derek says, then he should. The Chief's future remains up in the air, then, as he reconciles (at least somewhat) with Adele. He remains by her side throughout her operation, and afterwards, after they learn Adele miscarried the baby, she reveals it was Richard's child all along. Adele says she thought he'd go running for the hills, but she misjudged him. After all that's happened, there's hope for these two yet.

Jeff Pope, Rebecca's husband, comes to reclaim his wife. Like Rebecca said, her husband is a nice guy - one who admits privately to Alex that he didn’t pay enough attention to her. He loves her and is ready to bring her and the baby. Alex is disappointed, but when Rebecca tells him he’s the only one who saw the real her and begs him to give her a reason to stay, he can't. It seemed as if he was letting Rebecca go because he didn’t want to make her stay, only to disappoint her. Or because he can't face the fact that he's got real feelings for someone. Later, Addison (of all people) tells Alex he sucks, and that he can't leave life-changing opportunities on the table. He races back to Seattle Grace... to find Rebecca's hospital room tragically empty.

Elsewhere, Callie wants to have a baby, and after some deliberation, George is apparently into the idea. They even tried to make one in the break room, she reveals. Oh, and she was named Chief Resident, stunning Dr. Bailey and pretty much everyone else except her newly-confident self. But it's her and George that Izzie can't bear. Right before the Burke-Cristina wedding, Izzie confesses that she’s still in love with him after saying she’d do everything to support his marriage with Callie if that's what he really wants. They shared deep eye-contact after her profession of love, but nothing more. If he shares her feelings, he's not saying. George has other problems than his turbulent love life, however. He learns he didn’t pass his intern exam, although he doesn't tell anyone. Bailey knows, of course, and after asking if she failed him, says he can either walk away from being a surgical resident altogether, or repeat his intern year. George says it's him that failed her, and walks.

As he's cleaning out his locker, the newest crop of interns arrives, taking a self-guided tour of the hospital. A beautiful girl stays behind to ask him for advice, introducing herself as Lexie Grey. Lexie Grey can only be Meredith's half-sister, and is also recognizable as the girl Derek flirted with in the bar the night before. Amazing. Earlier, Derek admits to Meredith that he flirted with the girl in the bar and it was the highlight of his week. Later, though, he tells Meredith that he loves her and will never leave her, but she keeps leaving him. She comes and goes whenever it’s convenient. He tells her that if she’s not in it for the long haul, she needs to leave him for good. Meredith gets teary, remains non-committal and says she needs to go to help Cristina.

Just before the wedding, best man Derek tells Preston he doesn’t think he and Meredith are going to make it. He also lies and says he got turned down for the Chief of Surgery job, which we don't know to be a lie at the time. Cristina and Preston are about to get married. The moment has arrived. But after Cristina freaks out because her vows - written on her hand - washed off when she scrubbed in earlier that day, Burke goes out to find her and in a moment of clarity, decides he knows she didn’t want to marry him. He says she would, because she loves him, but doesn't want to. She tried to argue with him, but both knew what he was saying was true. In the closing moments, she goes back to their apartment to find Burke is gone. Meredith asks how she knows for sure, and Cristina points out the absence of his trumpet, jazz collection, lucky scrub cap and a picture of his grandmother. They're all missing. Cristina tells Meredith she’s free, then bursts into tears. Anxiety consumers her and she begs to get out of the dress. Meredith literally cuts the back off it as she collapses into her arms in emotional anguish.

Imagine having to take one of the biggest exams of your career, while at the same time stressing over your wedding day (tomorrow), being blamed by your father for your stepmother’s death, falling in love with your best friend - also a married man - or worrying about a patient with amnesia who may have gotten her memory back but won't admit it. As Season 3 of Grey's Anatomy draws to a close, all these issues and more are on the table.
Addison has returned from Los Angeles, Derek is feeling unneeded by Meredith and Miranda has some unexpected competition (in the form of Callie Torres O'Malley) in her own race for the chief resident. George, we learn, was accepted for the position at Mercy West. Callie is thrilled, but no one else shares her enthusiasm when word gets around. Izzie, longing for him more every day, begs him not to go and he explains to her that he has to get away from her because he’s a married man and can't be kissing other women in elevators. Callie happens to see their heart to heart, and the body language gives her an indication of what's going on, even if she isn't fully aware of the love O'Mizzie shares. Later, Izzie tells George that the night they spent together meant nothing after all, so he doesn’t have to leave. She then finds an empty room and cries. Later that night, Cristina is still trying to figure out her vows (and downplaying the whole ordeal) when Izzie goes on a tirade about how all of them have the man they want, and how vows are so important. Meredith asks her if she’s talking about Denny and Izzie says yes, but the look on Callie’s face is knowing and that of outright suspicion. On the professional front, Callie is making quite the name for herself by assisting on three surgeries at the same time. Mark remarked that Callie was giving Miranda some competition for Chief Resident - a fact that Dr. Bailey clearly hadn't even considered. Later, Callie summed it up with a simple position: she’s qualified, so why shouldn’t she take a shot? Since learning she probably will never have children in L.A., Addison has naturally become surrounded by pregnant people. Joe and his boyfriend, Walter, bring to SGH a young pregnant woman who is considering them to be the adoptive parents of her twins. The surrogate mom is admitted with a case of bad heartburn, but collapses later that day due to something that looks a lot more severe. Adele Webber also arrives to see Addison after being in a fender bender and confesses that she too is pregnant. She's 52, won't say who the father is and wouldn’t stay the night despite Addison’s advice because there's no way she's going to let Richard know she was even there. But at the end of the day, the Chief spots Adele trying to bolt, and she runs to the bathroom. Clueless as to why she’s at Seattle Grace, Richard talks to the bathroom door for a few minutes and tells her to come out, promising that he has moved on and is dating... or at least intends to. Eventually, hearing no response, he goes in and finds her collapsed on the floor, unconscious, in a pool of blood. Stunned, Richard hollers for help. When Ava/Jane Doe is helping Alex study for his exam, she mentions that her daughter has her father’s nose. Alex does a double-take and realizes she remembers something. He's thrilled, but she brushes it off. He asks her if she remembers anything, she says no. Eventually he begins to suspect that she’s lying and calls her on it. After arguing for a bit, she admits that she does remember everything. She woke up the other day with her full memory back. She tells him she was so unhappy with her life and her perfect husband so she left him and came to Seattle. Shortly after, the accident happened and she lost her memory. Alex is upset, naturally, that she led him on and that she hasn’t gotten in touch with her family. He threatens to call the police, but doesn't. Later, she finds him and tells him her real name. It's Rebecca Pope. What will happen next with this patient that has tested Alex like never before? Despite "the slap," Meredith still plans to attend Susan’s funeral before taking the intern exam. But Thatcher shows up at Seattle Grace, still in shock and angry, screaming at Meredith again. Susan trusted her and then Meredith killed her, Thatcher says - and she was all he had. He tells her she is not welcome at the funeral and leaves. While the other interns put their personal lives on hold for a few hours to take their exams, Meredith is left reeling by her dad and stares blankly at her test, not writing a single thing. Afterwards, she goes to the lobby and just sits there. George finds the Chief to tell him what happened. Although Meredith previously lashed out at Richard for trying to act like her dad, he still cares deeply for Ellis Grey's little girl and lets her retake the test. She says again he’s not her father, but he puts his arm around her and Meredith finally cries, letting all that pain out. A trio of missing climbers are found and are brought to Seattle Grace for emergency surgery. One of their fellow climbers is still missing on Mt. Ranier, but the staff is concerned with their broken bones and frostbite. Throughout the day, though, we learn more about the missing man, the one left behind. They talk of him as though he died up there, but are clearly remorseful, and one of the them implies they shouldn't have left him. After their surgeries, the fourth climber is rushed into the hospital - having been found, alive, with a climber’s axe lodged in his skull. Dr. Bailey asks in shock, "What happened the happened on that mountain?" It wasn't what we were first led to believe, that's for sure, and it will be very interesting to see what happens when his compatriots learn of his arrival at Seattle Grace. As Preston and Callie perform surgery on one of the climbers, they discuss why anyone would go mountain climbing in the first place. Callie said she climbed all the time when she was in college, that it's hard work and you feel terrible doing it, but it’s worth it to reach the top. It shows you how strong you really are, deep down. Burke obviously relates, in terms of his relationship with Cristina. In one more day, he'll have make it to the top... but can he make the last push to the summit? Derek has been trying to be there for Meredith throughout the day, but she rejects his attempts and he’s getting sick of it. At the end of the night, he's having a few drinks with Burke, Addison and Mark at Joe’s as a small bachelor party for Preston, and questioning his relationship with Meredith once again. That's when a beautiful woman approaches him. She offers to buy him a drink and while he seems very attracted to her, he politely declines. He says he is with some friends, she says that's too bad, and he says yes, yes it is. Does this new girl spell trouble for Meredith and Derek? We will have to wait and see.