Oh, the Guilt

Izzie makes breakfast for her housemates. Worried that she is starting her obsessive muffin baking again, they ask her if she is ok. She insists that she is fine, but is being very cavalier towards her 8.7 million dollar check from Denny, even spilling juice all over it. Unable to decide what to do with the money, she decides to go the hospital to clear out her locker first.

The interns are excited to attend the Morbidity and Mortality (M&M) conference but their excitement evaporates quickly after finding out Denny Duquette is first on the agenda. Bailey is slammed and raked over the coals for letting her interns run unsupervised about the hospital for long durations. A Dr. Savoy, in particular, questions her authority as a surgeon, especially after her new commitments as a mother. While wandering around the hospital, Izzie stumbles into the conference and also witnesses the Bailey-bashing.

After the conference, the interns refuse to let Izzie be alone and insists she stays in the hospital. George offers to keep her company. Alex becomes very defensive and says that he was not involved in any part of the Denny debacle. Cristina and Meredith are very apologetic to Bailey, but she brushes them off as they do not get to feel better about the whole thing.

Bailey, Alex and Mark treat a young mother, Rebecca, battling stage 2B breast cancer, who is wondering if it is even worth considering a mastectomy when she feels as if she will die soon anyway. Feeling guilty over blaming the baby for not discovering the cancer earlier, forcing her to undergo the mastectomy, she decides against the surgery. Bailey keeps herself from becoming emotionally involved in the case, for fear of damaging her reputation any further, despite Rebecca's husband's numerous desperate pleads to Bailey to urge his wife to do the surgery. Noticing Bailey's uncharacteristic coldness, the Chief tells her that being a parent makes her a better doctor because compassion and empathy are large parts of being a doctor. Bailey decides to re-embrace her old warm self, she talks to Rebecca using her own experiences as a new mother herself. She tells her that mothers are only human and blaming the baby is a normal reaction. Rebecca is encouraged to fight the cancer so that she doesn't miss out on the joys of motherhood. Bailey is looking after the baby while the couple have some alone time, and Dr. Savoy approaches her. She rebukes him for undermining her authority and he leaves. The conversation is overheard by Alex, who tells Bailey that he didn't do anything. Misunderstanding him, she tells him that she knows he was not involved in the matter. He clarifies, telling her that he knew about Izzie's plan to cut the LVAD wire and he didn't do anything. Therefore, he was partly to blame as well. Bailey thanks him, calling him "Alex".

Derek and Addison finalize their divorce with Derek giving up most of their property to Addison. He feels she deserves it because he had an affair while she only had a one night stand with Mark. Also, Derek happily decides that they are mature and civilised, and wants to remain friends with her. Addison tries to clarify the truth, but cannot bring herself to say it.

Meanwhile, Burke cannot bring himself to tell the Chief about his shaky hand, especially after the Chief heaps praise onto him. He decides to bury himself in paperwork and abstains from surgeries. Izzie wanders into his office and tells him that she is fine. He castigates her, saying that she is not fine, because Denny died, and neither is he, because he got shot while returning to the hospital after she told him to. Feeling extremely guilty for causing Burke harm, she leaves his office.

Meredith contemplates telling Derek about her breaking up with Finn and her fellow interns urge her to do it quickly. She meets Callie, who unexpectedly confesses that she slept with another guy and asks if she should tell George. Feeling like she should share, Meredith tells Callie that she broke up with Finn and asks if she should tell Derek. She decides not to tell Derek while Callie resolves to tell George. Over the course of the day, she bumps into Derek many times but decides against telling him about Finn.

Meredith and Addison examine a couple, Sonya and Adam, who have become stuck together in mid-coitus. Adam's piercing hooked onto Sonya's dislodged IUD and is embedded in her vaginal wall. Guilty about having sex with her ex-husband even though she has re-married, she begs Addison to separate them quickly. Addison, Meredith, Cristina and the Chief manage to separate the couple but Adam suffers a heart attack in the process and Burke is called onto the case.

Burke and Cristina work out an arrangement for the surgery. In the midst of performing cardiac surgery, Burke's right hand begins to tremble again, so Cristina covers for him by asking to practice her running whipstitch. Burke talks her through the delicate procedure and this gets the other interns jealous. Izzie, however, is inspired watching Cristina in the operating theatre. This makes Izzie realise that despite all the things she could do now that she is rich, she still wants to be a surgeon. She speaks with the Chief and asks to return to work. The Chief tells her of his own past, when he made a mistake and lost a patient due to a collapsed lung. He tells her that she is only human and therefore capable of making mistakes, and that the important thing is to learn from your mistakes and move on.

Sonya tells Addison that she will tell her current husband about her affair because she stopped feeling guilty after repeatedly meeting her ex-husband for sex. She feels that the truth has to come out eventually. This makes Addison confess to Derek that she had a relationship with Mark for two months after he left. She only left for Seattle after finding him in bed with someone else. Derek tells her to get out of his life. Meanwhile, Meredith walks into the elevator and meets Derek. She tells him about Finn but still reeling from Addison's confession, he mutters an unenthusiastic "okay". A confused Meredith looks on as he leaves the elevator. Mark approaches him and tells him that he felt like he should know the truth because they are friends, to which Derek coldly replies that Mark is not his friend.

George goes to see Callie in her hotel room, bringing food and entertainment. However, she is still guilty from sleeping with Mark and tells him that they have broken up. Addison and Mark sleep together again, post-coital, he tells her that she need not feel guilty anymore, prompting her to say "shut up". Back at Meredith's place, Izzie decides not to cash her multimillion dollar check until she knows what good can come of it, to George's and Meredith's disbelief. Izzie places her battered check on the refrigerator and leaves. Meredith reaches out for it, only to have George playfully slap her hand away.