All the nurses at Seattle Grace Hospital go on strike, leaving the doctors to fend for themselves. George refuses to cross the picket line and finally joins the nurses on their strike while Alex, Cristina, Izzie and Meredith meets Bailey's stand-in: Dr. Cindy Aaron, the complete opposite of Miranda Bailey. Izzie agrees to work on a difficult pregnancy case with Addison, while Cristina and Alex are in the pit attending to a young married woman with a real bad case of rash. Meredith happens on an old woman that she needs to intubate and then learns she was DNR.

The men of Seattle Grace go on a camping trip together, Addison and Callie must team up to work on a patient, Meredith assists Sloan with a procedure unlike any she has experienced, and, suspicious of her recent actions at the hospital, Bailey confronts Cristina. A 9-year-old is seen by Cristina after he swallowed Monopoly game pieces. A pregnant 25-year-old, is brought in after she slipped in the shower. She doesn't want medicine to take away the pain from her injury so not to put her baby's growth in jeopardy. Doctors take care of Daniel, a man who wants a sexual reassignment surgery and who now goes under the name Donna. Accompanying Daniel is his wife of the past 10 years, who was surprised to see him want that surgery but, after much struggling, decided to stay by his side.

A mass trauma situation, which turns out to be a ferryboat accident, challenges the whole staff of Seattle Grace Hospital. Richard finds difficulty in coping with his separation from his wife and dyes his hair "for the ladies", which becomes an internal joke between Mark, Burke and Derek. Cristina tries to tell Meredith about her upcoming marriage, but doesn't have the strength to. George promises to find a woman's son, who has been separated from her at the accident. The woman refuses to go into surgery until she is assured that her son is alive. Izzie has to take care of a man who got stuck between two cars on the ferry, but nobody helps her due to the large number of injured people. Alex rescues a pregnant woman with severe wounds on her face, and promises to take care of her. Meredith looks after a girl who has been separated from her mother after the accident, but accidentally falls into the water and drowns, with nobody but the little girl as a witness.

Meredith is still underwater, but nobody seems to notice. Her worsening condition makes her rescuing an urgent matter. Derek finds her coat on a man she had helped, and starts looking for her and, much to his shock, the little girl Meredith took care of suggests that she is in the water. Derek saves her, but she is almost dead, due to hypothermia. Izzie has to perform brain surgery on a man stuck between cars, as he begins to experience seizures. She drills holes into his head, perforates his skull and ultimately saves his life before he is rescued and transferred to Seattle Grace Hospital. George lies to the woman whose son he had been looking for, in order to get to surgery, but still doesn't have any luck in locating him. Alex finds no hope in searching for the pregnant Jane Doe's family as she undergoes surgery. The interns find out about Meredith's situation and express their hopelessness. She wakes up in what appears to be limbo and meets her deceased acquaintances.

Everyone is pushing for Meredith to survive, or in this case to be revived. People are still dealing with the fallout from the ferry disaster. A young man named Lucas is having problems with brain-mouth coordination. Someone else dies.

The attendings vie to be Chief. Two people who haven't slept together before, will. McSteamy's 60-day vow of chastity has a conclusion. We meet a boss, his assistant, and his wife. We also get to see someone being treated in the clinic. Derek has more questions about his relationship with Meredith. The chairman of the hospital board is admitted as patient. Callie confronts Izzie about her relationship with George.

It's Halloween at Seattle Grace! There may be jokes, pranks, and/or scare tactics. Some of the women form a club based on an experience they all share. A man volunteers for what most of the doctors believe is an unnecessary surgery. One of the patients is in the hospital because they tried to carve a pumpkin in an unconventional manner.

There has been a bus crash and the patients are in the ER. Meredith and Derek's relationship gets more complicated when he dates a fellow doctor. Meredith's dad goes to visit her at the hospital.