'Grey's Anatomy' Season 4 Episode Guide

What Happened in 17 Shows

Ellen Pompeo

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Season 4 of "Grey's Anatomy" continued the show's momentum as one of the most popular medical-themed programs on television. It highlighted Derek and Meredith's breakup, segued into his romance with Rose, and featured enough drama surrounding other characters to keep viewers tuning in to every episode.

The season begins as the interns return as first-year residents—all except for George, who has to repeat his intern year. Each of the residents is assigned interns. Cristina is assigned Lexie Grey, Meredith's half-sister, who desperately wants to get to know Meredith. 

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4x1 'A Change Is Gonna Come' (OAD 9/27/07)

Derek tells Cristina that Burke put in his resignation two weeks prior. Derek and Meredith meet up, and she says that it's over between them. Of course, they seal the deal with a bit of breakup sex.

Izzie talks to George in the stairway, lamenting that she didn't hear from him for over two weeks after she told him she loved him. That night he comes to her house and tells her that he loves her, too.

Bailey is upset that Callie was made chief resident, and Richard tries to explain that it's because Callie is a great surgeon and belongs in the OR. He says she'll thank him for it one day, and she replies, "Not today."

Addison is gone, and Mark wants to have a drink with Derek but Derek refuses.

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4x2 'Love/Addiction' (OAD 10/4/07)

George decides to tell Callie that their marriage is over, but then Izzie asks him not to. Derek and Meredith have been seeing each other only for sex. Derek wants to stop, but can't.

Lexie keeps staring at Meredith, and Meredith tells her that she wants nothing to do with her.

Burke's mother gets the key from Cristina, and then moves the rest of Burke's stuff from the apartment.

Callie has a hard time running the residents, and Bailey is upset that Callie won't give her a resident for the clinic, only interns. Bailey begs Meredith to help her, and Meredith does.

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4x3 'Let the Truth Sting' (OAD 10/11/07)

Meredith feels sorry for Cristina, so she gives her a surgery. Meredith takes Cristina's interns, including Lexie. She tries to teach Lexie, but Lexie gets mad and Meredith sends her to the clinic. Bailey tells Meredith to talk to Lexie because her mother died and Meredith was Susan's doctor.

Bailey has a hard time with Callie being the chief resident and finally talks to her about it, suggesting that they be a team.

George tells Izzie that he will tell Callie on his own time. That night he tells Callie that he'd slept with Izzie. 

Cristina figures out that Meredith is sleeping with Derek. When the year-long coma patient that everyone has been calling the "Really Old Guy" wakes up, Izzie tries to save him. But he wants to die and finally does.

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4x4 'The Heart of the Matter' (OAD 10/18/07)

Izzie starts a rumor that Callie wants to beat her up. Callie is offended that Izzie would think that.

Alex is disgusted that Izzie told him he's like a girlfriend and that she slept with George.

Izzie cries at home.

Richard's niece is brought back into the hospital, but she doesn't want to undergo any further treatments to try and cure her cancer. Adele expects Richard to talk her into changing her mind, but Richard says he'll do whatever his niece wants.

Meredith gets stuck with Norman, the elderly intern. Because he reads a chart incorrectly, they tell a healthy patient that she is going to die.

Meredith tells Cristina that she hates the "idea" of Lexie, but the person herself isn't so bad.

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4x5 'Haunt You Every Day' (OAD 10/25/07)

Meredith dreams of her mother and feels she is being haunted, so she takes the urn out of her closet and puts her mother's ashes into a plastic bag and takes them to work. She wants to put her mother to rest, and ends up washing the ashes down the sink in the scrub room. Richard comes in and helps her.

When Izzie asks a question, Callie announces to everyone that Izzie slept with her husband. Izzie and George just try to make it through the day. Izzie apologizes to Cristina and tells her to cut Izzie some slack.

Cristina is looking for a roommate and tells Richard he can move in, but recants when he hires Erica as chief cardiothoracic surgeon after she'd judged Cristina for sleeping with Burke. Instead, Christina allows Callie to move in.

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4x6 'Kung Fu Fighting' (OAD 11/01/07)

Cristina spends the night with Meredith because of Meredith's nightmares. Meredith tells Cristina that she's not ready to give up that safe feeling that comes just after sex with Derek.

Callie tells George that she's letting it go, and George and Izzie plan the perfect night together. Only when the time comes, Izzie starts to cry because she's too exhausted from work and can only do so much.

Dr. Webber invites Derek and Mark to a gentlemen's night, and Erica is offended that she wasn't invited. He says she can come, and the four end up playing Monopoly.

Lexie goes home with Alex and sleeps with him, then is horrified to find out that he lives with Meredith, who finds them together.

Erica is keeping Cristina out of her surgeries.

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4x7 'Physical Attraction...Chemical Reaction' (OAD 11/08/07)

Izzie and George are distraught because they have no chemistry in bed, despite several attempts.

Callie asks Bailey to cover for her so that she can do some surgeries. Bailey does an excellent job, and the chief gets suspicious. When he figures out what is going on, he fires Callie and makes Bailey the chief resident. She cries and hugs him.

Mark asks Erica out, but she won't date him because she's not attracted to him.

Meredith asks Alex to stay away from Lexie, but after Lexie talks to Meredith, Meredith asks him to take Lexie home. Once there, he discovers that their father is about to drive drunk. They stop him, and Lexie asks Alex not to tell Meredith.

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4x8 'Forever Young' (OAD 11/15/07)

Drunk and with a bleeding hand, Thatcher comes into the hospital asking for Meredith. Meredith stitches her father's hand. He says he is proud of her and that he regrets every day missing out on her life. After talking to Lexie, Meredith realizes that he didn't mean any of it.

Bailey loves her new job as chief resident. An old high school friend comes in and flirts with her. Erica tells her she's a blathering idiot. Bailey soon figures out that the man is using her, just like he did in high school when she helped him with homework.

Izzie and George are no longer speaking, and it gets around the hospital that they broke up, which makes Callie happy. That night they talk and say they don't want to lose their best friend.

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4x9 'Crash Into Me: Part 1' (OAD 11/22/07)

Two paramedics are trapped in an ambulance that was just hit by a second ambulance after the driver had a seizure. A paramedic needs care, but tries to hide his abdominal swastika from Bailey, then Richard, then Cristina. Bailey brings George in on the paramedic's insistence that a white doctor be present during his treatment.

Meredith stays with the men in the first ambulance and realizes that Stan is going to bleed out as soon as they get him from the truck. He says his wife works in the hospital and Meredith gets her.

Mark has a patient whose carotid artery is covered by a light flap of skin after Mark removed a tumor. Lexie becomes friends with the patient and is talking to him about what a jerk Alex is. Suddenly, the artery bursts. Lexie freezes.

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4x10 'Crash Into Me: Part 2' (OAD 12/06/07)

Lexie tries to the stop the bleeding for the carotid artery that burst in her patient. Mark comes in and they get the patient into surgery, but he dies.

Derek works closely with Rose during surgery. Afterward, they kiss. Later, not knowing that this happened, Meredith tells Derek that she doesn't want him seeing anyone else.

Rebecca returns and wants Alex to call her Ava, but he says she's playing dress up and needs to go back to her husband.

Bailey fights with her husband, who says she is never around.

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4x11 'Lay Your Hands on Me' (OAD 1/10/08)

Meredith makes Lexie an omelet, which Lexie chokes down even though it's awful and she's allergic to eggs.

Tucker is rushed to the hospital after a bookshelf falls on him in Bailey's home office. They do surgery on him and he is alright, but Tucker goes home to pack his things to stay in a hotel.

Mrs. O'Malley shows Callie the baby clothes she'd been making. Izzie sees Mrs. O'Malley and thinks she knows everything and spills the beans. Mrs. O'Malley is very upset and tells George to go to counseling.

Meredith is unnerved because Derek is talking about building a house for them. She finds out about Rose and says she can't trust him. He says she can't trust anyone. He invites Rose out on a date.

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4x12 'Where the Wild Things Are' (OAD 4/24/08)

Derek is now dating Rose, and Meredith seems to get past it. She does research on a certain kind of tumor and wants to do a clinical trial. She asks Derek to be the neurologist for the trial because he is the best.

Lexie and George find an apartment, but George hates it because it's run down and full of cockroaches. Lexie fixes it up with stolen items from the hospital and tells George that he's her only friend. He apologizes for complaining so much.

Cristina wants Callie to put in a good word for her with Callie's new best friend, Erica.

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4x13 'Piece of My Heart' (OAD 5/1/08)

Addison returns to the hospital to perform a surgery and can't believe that Meredith and Derek broke up. She tells Meredith not to let him get away.

Rebecca tells Alex she's pregnant. One of Izzie's interns calls Izzie in because she can't find a heartbeat for the baby. Izzie explains that it can be difficult to find a heartbeat so early in the pregnancy. She runs a lab test, but it comes back negative for pregnancy.

Addison asks Callie if she and Hahn are a couple, which freaks Callie out and she sleeps with Mark again.

Meredith and Derek work on their clinic trial and lose their first patient.

Izzie is jealous because George hangs out with the other interns.

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4x14 'The Becoming' (OAD 5/08/08)

The nurses boycott Mark because of his philandering. Adele comes in as a nurse rep and wants all employees to write down any sexual history they might have with other employees.

Richard tries to show Adele how he has changed and uses George as the chief's assistant so that he can delegate. He also leaves early and he and Adele end up sleeping together.

Derek and Meredith work on their fifth patient for the trial. He lives for a while, but eventually dies. Derek presents Meredith with a bottle of champagne and tells her that they are going to open it when they succeed.

Derek tells Mark that he slept with Rose but thought about Meredith the whole time.

Alex makes plans to get a place with Rebecca, and it takes everything Izzie has not to tell him that Alex isn't pregnant.

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4x15 'Losing My Mind' (OAD 5/15/08)

Meredith fires her therapist for saying she is a quitter. Then she hires her back again.

Mark teases Callie and Erica about having a threesome, and Erica surprises them both when she kisses Callie.

George works hard as the chief's assistant and then takes Tucker while Bailey and Tucker fight.

Rebecca asks Mark to give her a boob job. He thinks something might be wrong, and Izzie tells him about the false pregnancy. He suggests she get a psych workup. Alex sees the ultrasound and realizes there was never any baby. Rebecca insists she had a miscarriage. Alex decides to take care of her, shocking Izzie.

Cristina is still not herself since Burke won the Harper Avery award. She sends Lexie to do a procedure on a VIP.

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4x16 'Freedom: Part 1' (OAD 5/22/08)

Rose tells Meredith that she is intimidated by her and by her and Derek's history. She then tells her that Derek is selling his land. Meredith asks him about it and he says he is moving on.

Derek and Meredith continue their clinical trials, but the chief says that they have until midnight that evening to save a patient or they will be shut down. They try for two and the first one dies. In a fit of frustration, Derek throws the bottle of champagne in the trash.

Callie is freaked out by Mark's suggestion they have a threesome with Erica.

George is upset that he's the powerful chief's intern but has no power. Lexie reads the files on the first year residents and tells George that he missed his interim exams by one point.

Meredith feels bad for Christina and gives her the sparkle pager, which means she is now first in line for the next surgery. 

Rebecca tries to kill herself.

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4x17 'Freedom Part: 2' (OAD 5/22/08)

In the season finale, Alex rushes Rebecca into the ER. After she is patched up, he insists he can take her home and take care of her. Later, after talking to Rebecca's husband and realizing just show sick she is, he tells her she'll have to be transferred to a psychiatric facility.

George pleads his case to Richard, asking to retake the intern test. Richard agrees. George is so excited that he kisses Lexie. 

Richard goes back to Adele and she lets him move back in. He tells Erica to lay off of Cristina and Cristina begins teaching Lexie. 

Meredith and Derek succeed with their next patient in the clinical trial. Meredith can't find the bottle of champagne, though, so she leaves. Derek pulls the champagne out of the trash, but now he can't find Meredith. He finally finds her at his house, where she'd taken candles and made an outline of the house they were going to build together. He kisses her and then says he has to talk to Rose so that he has a clear conscience. He tells her to wait there.