Best Episodes of Grey's Anatomy

Richard is determined to discover the guilty party, and punishes the interns by making them arrange a prom for his niece. Meanwhile, Callie presses George about his feelings, and Derek and Meredith have to make a decision about Doc.

In a series first, the music that has been at the heart of the show and been beloved by fans comes to life for Grey's Anatomy: The Music Event. A cataclysmic event rattles the doctors of Seattle Grace to the core, as Callie, on the verge of an enormous life-changing moment with Arizona, envisions her hospital and friends as it has never-been-seen before. "Chasing Cars" (Snow Patrol), "How to Save a Life" (The Fray) and "The Story" (Brandi Carlile) are among the songs performed by the cast.

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

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

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 Webber, Callie looks back on a polio case, and Richard recalls a case in which he and Ellis worked on a patient diagnosed with AIDS, known in 1982 as GRID.

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 effort to save their jobs.

A train wreck brings in multiple casualties, leaving Meredith hanging for her answer. Meanwhile, Alex finds working without his mojo a disheartening experience, and Cristina searches high and low for a missing appendage.

Meredith and Miranda each cross a line, William Dunn regrets his decision and Izzie finally confronts what Denny's appearance means.

Six hours after their oral boards, the fifth years relive their answers and worry about their chances. Back at the hospital, Bailey has to woo potential candidates for the hospital and Mark is startled when Julia makes a proposal about their future.

As Meredith, Cristina, Derek, Mark, Lexie, and Arizona face the aftermath of their accident, the doctors back at the hospital face the future that seems to be taking them all in different directions.

Teddy is called away on another case, as Henry is brought in for surgery.

Jackson's suspicions about Mark and Lexie interfere with work.

A documentary film crew visits the hospital six months after the shooting to document the road to recovery for doctors and patients. The camera lenses follow Derek, Owen, Mark & Callie as they ambitiously perform a rare arm transplant surgery, Meredith helps Cristina put on a brave face for the cameras, and Bailey's patient, Mary, returns for her surgery -- which marks the first time they've all seen of each other since that fateful day.

An unconscious Meredith interacts with some ghosts from her past while Richard, Burke and Bailey devise an unusual method of reviving her. A despondent Cristina leaves during her shift, and Derek speaks his mind to Meredith's mother.

While Meredith faces the consequences of tampering with the trial Cristina and Owen fight over an unexpected pregnancy.

Despite Meredith's objections to the idea, a concerned Derek takes Cristina on a fishing trip in order to get away from it all, while Teddy, feeling directionless without Cristina, directs all of her efforts and compassion towards a dying patient who lacks the proper insurance to seek medical treatment.

Meredith, looking to prove she is Chief Resident material, learns that anything and everything can happen in an hour's time when she steps up to run the ER for a night; meanwhile, Bailey sneaks off with Eli and gets into a little mischief, and everyone is surprised when the Chief's wife, Adele, shows up as one of the ER patients.

Izzie's memory problems panic Alex, the team takes care of a John Doe who was hit by a bus, Bailey rethinks her pediatrics fellowship, and the hospital endures losses.

A car crash involving students going to their college graduation takes its toll on the residents in the ER, Derek's wedding gift is uniquely suited for Meredith - even if the oversight is not. Meanwhile, Denny's return has Derek and Bailey searching for the cause, and the results will change the outcome of the day.

Owen's PTSD endangers Cristina, Izzie's illness leaves the residents dealing with guilt and anger - at her expense, and Derek's fear causes him to persevere for Meredith's answer.

Meredith deals with her over protective stepmother, Cristina is caught between Burke and Marlow, and Derek fights to become Chief. Meanwhile, Alex continues the search for Jane Doe's identity, and Izzie's past comes back to haunt her.

A toxic patient wreaks havoc. Meanwhile, Bailey opens the free clinic, but the lack of patients makes Izzie question her investment. Meredith's mother is admitted again, and Cristina makes Burke wait for an answer.

Guilt causes different actions in everyone, the interns are allowed to attend an M&M meeting, and Derek and Addison finalize things.

The victims of a workplace shooting are admitted. Izzie puts her job on the line to ensure Denny gets a new heart, Callie makes an effort with Meredith, and Addison is suspicious of Derek.

Burke is admitted as a patient, along with Richard's niece. Izzie and the others fight to keep Denny alive, while Alex tries to secure the donor heart for him.