"Can you direct me to the Space Needle?" Cristina poses this question to a cyclist on the street. She's lived in Seattle for years, but never really explored the city. The Space Needle is west, but Cristina heads east. She's following a caravan of ambulances. Something has happened. Something everyone a Seattle Grace has been through before. Something that nearly destroyed Dr. Cristina Yang.
A gunman opened fire at Pacific College. Many of the wounded are heading to Seattle Grace. A 21-year-old kid got an emergency thoracotomy at the scene. Both Owen and Teddy are shocked to see Cristina in the back of the ambulance with her hand inside the guy's chest. They wheel the patient into surgery. Jackson is asked to assist, just in case Cristina falls apart. But she seems to be doing just fine.
The cop who shot the gunman took a bullet himself. He's unconscious, so the Chief must perform a painful procedure to wake the officer long enough so he can give a description of the shooter. The Chief informs Teddy and Cristina that the kid they are trying to save is actually the gunman. Lexie and Jackson refuse to help this particular patient. As for Cristina, she's staying.
A dozen more shooting victims flood into the hospital. No operating rooms are available. Owen has a plan, but he doesn't look all that confident about it. He sets up the trauma rooms as if they were operating rooms and orders April to create the equivalent of a MASH unit in Outpatient Recovery. Looks like that trauma training she got in That's Me Trying is about to pay off!
Alex's patient is a 15-year-old girl with gunshot wounds to the leg and abdomen. Dr. Stark wants to do an amputation. Alex thinks they can save the leg. He sees Arizona in the observation room and pleads with her to do something. Arizona hustles to get privileges from the Chief as Alex body-blocks Stark from getting anywhere near that leg. Callie assists Arizona as a frustrated Dr. Stark storms out of the OR.
The men and women of Seattle Grace work with speed and skill in what Alex describes as a "mosh pit" of surgery. April stabilizes the hero cop. Mark gives Lexie the support she needs to pull her patient through. Alex and Jackson do their best to save a student, but it's only after Bailey's unyielding words to the man upstairs that the kid starts to improve.
Derek operates on a professor who helped students onto the roof before falling to the ground. He doesn't understand why Meredith keeps running out to update the guy's wife. It's because she was that very same worried wife just six months earlier. Meredith asks everyone in the waiting room to follow her. There's something they need to see. It's the Pacific College alma mater holding a candlelight vigil outside in a stirring, emotional show of support. Chills.
Many patients are treated and all of them survive the day. This is wonderful news to the families. Only the shooter's mother is still in agony, as she has no idea what's happening with her son. Jackson realizes that she is also a victim. He comforts her by telling what he knows along with the promise of an update. He then heads off to the OR observation deck as Teddy and Cristina continue to work on the gunman.
All our favorite docs are watching as Teddy and Cristina operate. Their patient will also survive. First, there are tears. Then smiles. Then joyous laughter from everyone but Dr. Stark, who says he hates this place. He doesn't quite fit in like Arizona, which is why the Chief hires her back. Of course, she'll have to report to Stark. Now everyone laughs even harder except, of course, for Arizona.
At the end of the day, Lexie says she'll wait for Mark while he does some cleanup work on a patient he couldn't tend to earlier. Callie simply can't forgive Arizona for leaving. Teddy has a drink with Henry, her nice, new husband she married for insurance purposes only. As for Cristina, she's finally back where she belongs—walking the halls of Seattle Grace with Meredith by her side.