Trama

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.—ABC Publicity

Arizona's air bag has deployed but Callie went through the windshield. Callie is taking over voiceover duties and has visions of herself watching the crash scene while telling about the mysteries of the human brain -- and how things get even more mysterious when the brain is traumatized.

Suddenly, the Callie she's envisioning sings the opening lines to the "Grey's" theme song. Welcome to the "Grey's Anatomy" musical event, which will feature the cast singing some of the show's most memorable songs as Callie dreams about the hospital in a whole different way.

Meredith comes into an O.R. with news for Sloan, who is impressed with his own surgical skills. She has something to tell him. We next see Sloan running out to wait for the ambulance and the chief tells him he has to "sit this one out." The chief explains to Sloan that Callie and the baby are his family, so he needs to sit back and let the doctors save their lives. Sloan demands he be allowed in the room.

The ambulance arrives and Arizona jumps out, injured but still giving instructions to the other doctors. Callie mumbles something about a song. As the doctors start working on her, her alternate self starts singing "Chasing Cars." As Hunt rolls her to an O.R., she imagines him singing the song, too. And she starts to cry.

As the doctors wheel Callie away, Sloan asks Arizona what happened. She tells him, "I asked her to marry me and a truck came out of nowhere."

There's chaos in the room as doctors shout instructions at each other, but Callie seems to be finding peace in Hunt and her alternative self harmonizing. Bailey soon joins in. The doctors get a read on the baby's heart beat. Next, they successfully get Callie's heart beating.

They roll Callie into an elevator and Arizona watches, stunned, as the doors close. Then she says to no one, "I asked her to marry me and a truck came out of nowhere."

Hunt has to calm the doctors down for fear that if they rush what they're doing, they'll make mistakes. Lexie leans in and urges Callie to relax while the doctors do their work. Then Lexie starts singing "Breathe."

As the doctors work on Callie, she's bleeding too much for them to take a chance on continuing to operate. They decide they have to close her up and give her 24 hours in the ICU, hoping she'll live through it. The chief asks Fields what her plan is for the possibility that Callie contracts again or she has to deliver the baby early. Fields admits to the chief that she may be a little out of her depth.

Lexie, still singing, finds Sloan crying in the stairwell. He tells her she doesn't have to be there because he knows she hates him. She sits next to him and tells him she doesn't hate him. Alex, meanwhile, sits next to Arizona in the gallery and asks if there's anything he can do. She cries on his shoulder. Back in the stairwell, Sloan tells Lexie that Callie is his "best friend."

Fields and Alex are on the roof of the hospital and Fields is embarrassed that the chief benched her. Alex tells her to suck it up and that the chief is only worried about doing what's best for Callie. They're waiting for a helicopter and when it lands, out comes Addison.

Addison goes straight to work on Callie and is upset with Fields for failing to stop the contractions, she didn't give steroids to the baby to help mature her lungs. She tells Fields to go. She then tells Callie that the doctors are going to make a plan and everything is going to be OK.

The doctors volley suggestions around a room until Hunt finally yells at them to calm down. This leads into a song. Outside the room, Alex says the only way to save the baby is to save Callie, and the only way to save Callie may end up killing the baby. Then they notice a hickey on Alex's neck and tease him about Fields. Alex tells them not to hold out hope, and makes the most obvious self-referrential joke possible, saying that Lucy "works at Seattle Grace Mercy Death, so I'm sure she's pretty much gonna go crazy or get cancer or shot by a gunman or get hit by a truck, so don't get your hopes up for Karev's big happily ever after."

Throughout all this, Hunt is singing, "How We Operate."

Bailey gives Sloan and Arizona the options about focusing on Callie or the baby. Sloan wants to make the effort to save Callie first, but Arizona is focused on the baby because that's what Callie would want. Through the shouting, Bailey starts singing, "Wait." During this song, we also see Cristina looking at heart scans and Derek telling Meredith that Callie may not come back because of the trauma to her brain.

Sloan and Arizona get heavy into their argument, with Arizona calling him "basically a sperm donor" and saying that she and Callie are together. Sloan turns it around on Arizona and says he's "the father" and this is his "family." He tells her she's "nothing."

Cristina takes a closer look at the scan and tells herself, "Wait."

We see Callie still unconscious and in a dream sequence, she rewinds the day all the way back to moments before the crash. She thinks about things going differently and anticipating Arizona's proposal. She then starts singing "Running on Sunshine," which leads to us seeing most of the other couples singing the song to each other. Her dream is interrupted when Derek tells her he's going to lower her sedation so they can check her neuro-function. Derek tells Sloan and Arizona it's "too soon to tell."

Cristina makes her case to Hunt and Teddy about a procedure Burke used in cases similar to Callie's. Teddy thinks it's too risky and says the conversation is over. Cristina turns to Hunt, who agrees with Teddy. Cristina leaves.

Arizona talks to Callie, who is sleeping, and tells her she's worried that Sloan is right about her being "nothing." This leads to them singing "Universe & U" together.

Soon, Callie is bleeding out.

Callie sings Kate Havnevik's "Grace" and the rest of the female characters join in as she's wheeled into an operating room.

Sloan and Arizona sit in the gallery and watch. Arizona suggests they pray, because Callie would want them to. Sloan tells her he hasn't stopped praying "since yesterday."

There's blood quickly into the surgery and Teddy struggles to fix it. Hunt says they have to go with Cristina's previous suggestion. Hunt tells Teddy to stop. When she doesn't, the chief commands her to step back. Cristina begins and Hunt starts the whole group singing "How to Save a Life." They're watching Callie's vitals and scrambling to work things out as the song increases in volume.

Addison tells the chief she's giving the group one minute to get Callie's heart going again, or she's taking the baby out.

Arizona and Sloan watch intently from the gallery, then jump to the O.R. Addison passes the tiny baby to Fields and tells her to try to get a heart beat. Sloan turns to look at Arizona and they share a nod before Arizona jumps into the mix and takes over trying to get the baby's heart going. She does it.

Derek, Sloan and Arizona wait for Callie to wake up, and wonder what to expect. Derek says there's a chance "she's not going to wake up."

After Derek leaves, Sloan tells Arizona she's "not nothing." He adds, "We have a kid together. You're a mom, I'm a dad. I'm sorry." Arizona insists that Callie has to wake up.

Meredith is crying in the elevator and admits to Derek that at Callie's baby shower, she was jealous because Callie got pregnant without even trying. She wonders why the universe is so screwed up that it would give Callie a baby and then put her through a windshield. Derek hugs her and promises her they'll have a baby, one way or another.

Arizona tells Callie that her baby is small, but really strong. "One pound, one ounce of strong." She tells Callie, "She can't open her eyes yet, but I can tell she's looking for you."

Callie starts singing "The Story." Avery, meanwhile, tells Lexie he isn't the kind of guy who waits for the girl who's still in love with another guy. She says they should go home together. Teddy tells Cristina she can't teach her any longer if she refuses to listen and learn.

At the peak of her song, dream Callie grabs real Callie's legs and jolts something in her. Callie's eye flutter open and she can barely get the words out, but tells Arizona, "Yes. Yes, I'll marry you."