Everyone has flashbacks of big moments in their lives. Izzie lies down on the bathroom floor at home and won't get up or take off her prom dress as she mourns Denny's death and the loss of her job.
Christina is caught seducing Burke in his hospital bed by his parents. Meredith tries to decide between Finn and Derek, but finally comes to the conclusion that she will try dating both of them.
Meredith begins dating both Derek and Finn, but she soon realizes they are more interested in competing against each other than wooing her. George isn't ready for Callie to move in, but isn't ready to tell her that either.
Izzie meets Denny's father, who gives her a generous gift. Meredith wonders if she's pregnant, but it turns out she needs her appendix removed. On drugs, Meredith continuously embarrases herself. Mark takes a job at Seattle Grace which distracts Addison from her work. Cristina pushes Burke to get back into doing surgery which he is not ready for. Derek tells Meredith to choose Finn, but Meredith tells Finn that she chooses Derek.
Addison and Derek finalize their divorce. Derek takes the blame for the marriage ending, but apparently Addison has not told Derek the entire truth. Meredith struggles with whether or not she should tell Derek that she broke up with Finn. At a meeting, Dr. Bailey takes on all the blame for Denny's death. A couple is brought into the hospital who are stuck together by an uncomfortable piercing.
Cristina scrubs in on all of Burke's surgeries, making her fellow doctors envious of her. She makes a risky decision when she hears that Bailey wants to scrub in on a "humpty dumpty" prcedure that Burke is signed up for.
The men of Seatlle Grace go on a camping trip. While on the trip, George makes fun of Alex, so Alex tells him that Callie slept with Sloan. The two want to fight it out, but Dr.
George suspects that Dr. Burke's hand isn't well. Then, George's father is diagnosed with a leaking heart valve and stage three cancer. George asks Cristina to tell him the truth.
George asks Dr. Hahn from Seattle Presbyterian Hospital to perform the surgery on his father. Burke is called into the Chief's office, and Cristina is afraid that George has told on them.
Bailey, Izzie, and Alex are upset because the Chief does not punish Cristina for keeping Burke's secret. George is especially upset since she let Burke operate on his father. Burke tells Derek he doesn't want him to operate on him again, which infuriates the Chief. Meredith deals with her half sister and step-mother. Meanwhile, a set of adult conjoined twins want a separation procedure.
Meredith discovers that her snoring keeps Derek awake at night. A girl with extreme spinal problems is admitted to the hospital. Callie wants Derek's help in performing a radical surgery.
Many people at Seattle Grace are having trouble sleeping. Meredith's snoring is still keeping Derek up. Thinking about her father is still keeping Meredith up.
Rumors are flying that Richard is stepping down as Chief of Seattle Grace, and many would-be successors begin jockeying for the position. Derek is angered when he discovers Preston was the Chief's first choice and then even more angered when he finds out that Meredith let the news slip to Mark.
The Denny Duquette Memorial Free Clinic opens. Izzie is worried it won't be succesful. They only get one patient, but Bailey is pleased with their work.
Meredith is upset over the hurtful things her mother said to her while she was lucid. Derek finds her completely underwater in her tub, and is afraid she was trying to drown herself.
Izzie calls the Chief and asks him what to do about the man trapped under a car. He and Sloan guide her through drilling holes in his head so that he won't die.
The doctors continue to try and revive Meredith. Cristina, unable to cope, goes on a shopping spree and then to the bar. Burke finds her and tells her to go back and say goodbye to Meredith.
Alex has moved into George's old room. Dr Colin Marlowe, a visiting cardio-thoracic specialist arrives and everyone is out to impress him, except Cristina who used to date him when he was her professor.
In his hung-over state, George does not remember the night before. Izzie does, but doesn't tell him. George goes to meet Callie's father, his new father-in-law.
Izzie faces her past when her 11 year old daughter needs her for a bone marrow transplant. and finds comfort in George, while Alex becomes more attached to Jane Doe, Meredith and Derek question their own status and Cristina resolves to fight for her relationship with Burke despite her past with Colin Marlow.
As the interns of Seattle Grace cram for their upcoming exam, the attendings vie for the Chief's position by tending to the chairperson of the hospital board after he is admitted as a patient. Meanwhile, Burke struggles to involve Cristina in the wedding planning, things heat up between Addison and Alex, and Derek questions his relationship with Meredith.
Part one of a two part episode where Addison takes temporary leave from Seattle Grace and makes a road trip to Los Angeles in order to visit some old friends from medical school.
Part two of a two part episode in which Addison's vacation to LA becomes less relaxing when she decides to help out at the private practice. She struggles with learning that she can't have a baby and feeling like her life is in shambles.
Exam day has arrived for the interns - and not everyone is ready. Meredith is blamed by her father for her stepfather's death and freezes during the exam.
The fourth hiker arrives at the hospital with an axe in his head. The other hikers first say it was an accident, but then admit that they did it on purpose.