Episode 1 | Good Mourning

Covering days one through 13, everyone at Seattle Grace fights to save Izzie and George's lives and then deals with the aftermath. Elsewhere, Hunt treats a double amputation, and Arizona has a teen with painful growth spurts.

Episode 2 | Goodbye

During days 20 through 40 the staff continues toward acceptance. Meanwhile, Arizona takes a manipulative step to diagnose her pain patient and Hunt's amputee patient sinks into a deep depression.

Episode 3 | I Always Feel Like Somebody's Watchin' Me

As hospital personnel jockey for notice to keep from being fired, Izzie returns to surgery early and Bailey's triple aneurysm patient refuses her procedure because of her schizophrenic son.

Episode 4 | Tainted Obligation

Thatcher is hospitalized with liver failure, and Meredith fights anger and guilt while deciding her responsibility. Sloan treats an octogenarian who wants an implant. Izzie's interference in Hunt's cancer case may have deadly cons...

Episode 5 | Invasion

As Mercy West merges with Seattle Grace, battle lines are drawn between the two hospital's residents over the patients.

Episode 6 | I Saw What I Saw

After a burn victim unexpectedly dies in the midst of a chaotic ER, the Chief and board member Jennings interrogate the residents to find the culprit, as all the Mercy West and Seattle Grace residents defend their actions in an ef...

Episode 7 | Give Peace a Chance

When Isaac, the hospital lab tech, has an inoperable tumor wrapped around his spine, he turns to Dr. Derek Shepherd to do the impossible, and Derek tests the Chief's authority when Richard objects to moving forward with the risky ...

Episode 8 | Invest in Love

A generous donation is offered to Seattle Grace by the parents of Arizona's 10-year-old patient. When his condition worsens, however, she finds herself with a conflict of interest. Meanwhile, Cristina tests her boundaries with Owe...

Episode 9 | New History

When Owen recruits his fellow Iraqi War vet, Dr. Teddy Altman, as the new cardiothoracic surgeon, Cristina questions Teddy's abilities in the OR and the nature of their past relationship. Meanwhile Izzie returns to Seattle Grace w...

Episode 10 | Holidaze

As Thanksgiving, Christmas and New Year's pass, Miranda is visited by her father, William, who disapproves of her choices in life; meanwhile, Mark and Lexie must cope with the shocking arrival of a woman from his past, and Thatche...

Episode 11 | Blink

Mark flies Addison to Seattle to help with a difficult procedure on his pregnant daughter, Sloan. Owen questions Teddy's motives when she assigns Cristina the lead on a complicated surgery, and Derek's suspicions are raised when t...

Episode 12 | I Like You So Much Better When You're Naked

After learning of Richard's drinking problem, Derek confronts him for the sake of his friend and the hospital, Izzie returns, hoping to reconcile with Alex, and tensions run high between Teddy, Cristina and Owen in the aftermath o...

Episode 13 | State of Love and Trust

An intra-operative crisis casts a shadow over Derek's first day as interim chief, Owen's influence worries Cristina, Karev's first pediatric surgery case turns out to be more than babysitting and Webber resents the decision he mus...

Episode 14 | Valentine's Day Massacre

It's Valentine's Day and the doctors must treat dozens of injured people after the roof collapses at a popular romantic restaurant; Derek tries to manage his busy schedule as Chief of Surgery; Meredith wrestles with her new duties...

Episode 15 | The Time Warp

In his new role as Chief, Derek restores the hospital lecture series, and several attendings present to the group pivotal surgical cases from their pasts: Bailey reflects on how shy she was as an intern until getting advice from W...

Episode 16 | Perfect Little Accident

When Avery's grandfather comes to the ER, Webber's wish for a stress-free first day back is lost after the surgeon requests an awake surgery. Elsewhere, Cristina and Teddy attempt a hand-me-down lung transplant for a cancer survivor.

Episode 17 | Push

A patient who needs an extremely difficult surgery comes to Seattle Grace, and it's Richard and Owen who vie for the opportunity to tackle it. But the decision lies in the hands of Derek, who deems that Owen should take on the sur...

Episode 18 | Suicide Is Painless

When Teddy's patient seeks to end treatment and her life, she turns to Hunt for help. The situation triggers Hunt's memories of his life at war and his past relationship with Teddy. Meanwhile, Callie and Arizona have a difference ...

Episode 19 | Sympathy for the Parents

Alex's brother Aaron comes to Seattle with a hernia and needs a pro bono operation. Having children is on everyone's minds and tensions are high because of it.

Episode 20 | Hook, Line and Sinner

Sloan returns to Mark's apartment just as she's going into labor. Teddy, Mark and the still-fighting Callie and Arizona are there to help with the birth and to get Mark through his grandson's pending adoption. Meanwhile Teddy sees...

Episode 21 | How Insensitive

Bailey preps the team with mandatory sensitivity training prior to admitting a 700-pound patient with compounded medical issues, and the case proves to be challenging. Meanwhile Derek has to come face to face with a former patient...

Episode 22 | Shiny Happy People

An elderly patient admitted into the E.R. for a heart condition sees a familiar face, a long lost love who happens to be in the E.R. as well for a fractured arm, and the staff find themselves caught up in their love story. Meanwhi...

Episode 23 | Sanctuary

Seattle Grace Hospital is hit with a crisis like no other in its history.

Episode 24 | Death and All His Friends

Cristina and Meredith's surgical skills are put to the ultimate test.