The episode begins and Meredith’s motherly instincts tell her that Zola is awake in the morning and Derek confirms she's right. Callie is nervous about speaking at a conference and Arizona helps her picture the audience naked, by getting naked. Cristina and Hunt rush to the hospital after hearing about a gas tanker accident. At the hospital, Alex interrupts Jo's make out session with Dr. Myers. Jo comes out and checks in with Casey, whose son Parker is sick. His fever is high and he now has a rash, but Jo says it isn't that unusual. Casey has been doing some online research and feels like her son doesn't have a virus, so Jo says she'll check it out.
Hunt talks to Derek about not just using Shane, but also giving other interns an opportunity. The victims from the gas tanker crash are starting to come in and the doctors are immediately hit with fumes. Hunt warns that there is to be no smoking or flame anywhere, and no cauterizing. The first woman wheeled in is 42-year-old Rachel Dawson, who is asking about her son, Ethan. Another man is wheeled in, it's her husband Paul. He's also asking about Ethan, 11, who is in the next ambulance and is asking about his parents. Jo tells Casey that her son tested positive for strep throat. She's relieved that it’s nothing serious. Bailey is checking a victim from the crash who wants to go outside for a smoke. Ethan is checked out and wants to see his parents. Hunt takes him to see his dad, who needs a CT scan quickly.
While Paul is wheeled away, he assures Ethan that he's going to be fine. Hunt takes Ethan to see his mom, but is informed that she's been taken to radiology. There's an explosion and it’s shown that the guy who wanted a smoke is outside the ER doors engulfed in flames. Jackson rushes the man for treatment. April gets a patient named Elise who tells her to focus on doing all she can to save her baby girl. April says she'll try to save them both. Derek and Shane check Rachel's scans and she has a hemorrhage in her brain. April is working on Elise and her unborn baby. Alex comes over to help and tries to adjust the umbilical cord.
While Alex wheels Elise away, April turns around and sees Matthew is in the E.R., as a patient. He explains that he ran into the crash to shield a kid from the blast with his own body. His back and leg are in a bad shape. He tells April he'll be fine and Jackson takes a look. Callie gets to the hospital hoping there's no surgical work because her flight leaves in four hours, but its clear there will be. Cristina is working on Paul and tells Hunt she’ll need another hour before she knows more. In surgery, Derek is a little annoyed with Heather, who is assisting him, because she is a bit too cheery. Heather whispers to Shane that Derek makes her nervous and she just wants him to like her. Shane drops an instrument, Heather catches it and on seeing that Derek praises her fast hands.
Myers gets Elise's baby out, but Elise is losing too much blood. Leah tells Hunt that Social Services have come for Ethan, who isn't happy about it. Hunt asks if he can keep Ethan in a room for the night and Ethan likes it. The father of Elise's baby comes and sees her and Myers hands the baby to him. Casey is back and says her son's fever is getting worse. She says this is the third hospital she's been to this week and she's determined not to get pushed around this time. Derek gives Shane instructions on what to do next with the patient, and has some fun by tossing things over his shoulder to Heather, who catches them all.
Jackson is treating Matthew, which makes April uncomfortable when she walks into the room. Jo brings a psychologist over to talk to Casey, who gets upset. She insists she's not crazy, and her son is actually sick. Meredith sees all this from afar and tells Casey that she believes her, so she tells Jo to admit her son. The social worker has lost Ethan and Hunt goes to look for him. Ethan is walking around looking in the rooms for his parents. He sees his mother's in a bed and runs to her, but she doesn't recognize him and starts shouting. Ethan is stunned and Hunt walks in while this is happening. Hunt explains to Ethan that his mom had a serious head injury, which could be causing her to act weird for now. Hunt tells Ethan to stay with the social worker.
Derek, Shane and Heather look at Rachel's scans and Shane gives Derek a recommendation, which Derek thinks is right. Meredith tells Casey that her son's scans are completely normal, but Casey isn’t convinced. She feels her son has Kawasaki disease, but Meredith says that he isn’t exhibiting much of the symptoms associated with that disease. Meredith thinks its strep, but tells Casey she will run some more tests. April walks in on Elise's husband talking to his wife in her sleep. He kisses Elise on the head and goes to see the baby. Callie and Webber come to Bailey and tell her to map their genomes, but she says her research is not a toy. Cristina gets a page about Paul, while April goes to check on Elise, who is in a bad shape.
Cristina gets Paul's pulse back, but April isn't as fortunate with Elise, who passes away. In surgery, Derek lets Shane open up part of the skull and tells Heather to step up and do the next part because he is impressed with her fast hands. Meredith tells Casey she can't find anything wrong with Parker other than the strep. Casey says the feeling that there is something wrong with her son won't go away. She asks Meredith how she can get rid of this feeling, but Meredith says nothing. Alex tells Myers, Elise didn't make it and says the news should come from him. Myers says she's not his responsibility and Alex isn’t happy with his reply and angrily storms off to covey the news himself. Meredith calls Jo over to run through Parker's test results again.
Jo says the labs just updated and the strep culture gave a false positive meaning it’s actually negative. She checks Parker's eyes and sees they're very red and tells Jo to prep treatment for Kawasaki disease. If they start immediately, they can avoid permanent heart damage. A shaken April watches through the nursery window as Alex breaks the news to Elise's husband. She sees him cry and goes into the room to put her hand on his shoulder. Casey is crying too, as she is looking through the window of her son's room.
Meredith comes and shows her scans of the fluid around his heart. She says the IV will fix it and he's going to need another echogram in six months. She tells Casey she saved her son's life by not giving up. Derek tells Shane that Heather is going to be assisting him for the rest of the week. Arizona brings Callie to a meeting room and there's a video production set up. Webber made some calls and arranged for Callie to give her TED speech on live video. Callie is nervous, but sits in the chair and is live just seconds later. Callie gives a heartfelt speech and Arizona is impressed. April goes to see Matthew and tells him about the patient who died and left her husband with a new baby. She says it doesn't make sense and Matthew tells April that he gets it. He insists he's fine, isn't going anywhere and he loves her. April looks a bit surprised on hearing this.
At the bar, Shane finds Heather and tells her he knows what she's doing and he insists he's not going down without a fight. Back at the hospital, Hunt brings Ethan to see his mom, who is sleeping and assures Ethan that both of his parents have a lot of good doctors taking care of them. Casey is sitting in her son's bed and he's made a drawing for her. Meredith comes to Bailey and tells her to map Zola because she doesn't know about her background. She wants Bailey to map her too because she wants to know if she's going to get Alzheimer's. Bailey says nothing, but only nods. The episode ends at this point.