We open to see Callie preparing for her big speech at the TED Conference. Yes, Callie is speaking at the TED Conference, even though she has a horrible fear of public speaking. But that’s before the hospital is overrun with patients when a gas tanker flips on the highway, exploding shortly after. Before the incoming patients arrive, Alex finds Jo and Jason making out, so he knocks on the window and demands she check her pager. Jo goes downstairs to see a familiar patient she treated the other night. His mother, Casey (guest star Sarah Chalke), explains that her son’s fever keeps spiking and he has a rash. She just knows something is up and it’s not a virus. Motherly instincts.

Meredith comes over to talk to Casey, who’s rambling off possible medical illnesses she found online that match her son’s symptoms. It turns out that her son just has strep throat, according to his positive test. Mystery solved? Not so fast. Casey brings her son back because it’s not strep throat, contrary to the positive test, and he’s getting worse. After her anger gets the best of her, Casey asks for another doctor. Jo calls for a psych consult when she learns that she’s been to two other hospitals this week, but Casey insists she’s not crazy – she’s just a mom. Meredith comes over and reaffirms her that she believes her. Meredith knows, she’s a mom, too.

Owen tells Derek he can’t play favorites so he’s forced to take Dr. Heather “Mousey” Brooks on his service, in addition to Shane. Contrary to his initial hesitations, Derek realizes that Brooks is a good intern – and a fast thinker. Shane is visibly jealous when Derek becomes so impressed with Brooks that he decides to have her on his service this week. Later that day, Shane insists that although he’s off Derek’s service this week, he’s not going down without a fight.

Bailey finally emerges from her lab (for the first time in a week, according to the doctors) after she learns there was a tanker explosion. Bailey works with Richard on a patient who’s covered in gas. The patient keeps asking to have a cigarette, which isn’t the brightest idea considering he’s covered in gas, but they deny him. Eventually the patient ignores their advice and goes outside for a smoke, resulting in him catching on fire.

Ambulances bring in several patients who smell heavily of gas. Owen meets a young patient, Ethan. His parents were involved in the tanker accident, too. He stays close to Owen while his mom gets a CT and his dad is rushed to surgery. Owen tells a nurse to call social services for the boy, who fails to leave his side. Instead, social services sets up a room for him nearby. He runs off and finds his mom, who doesn’t know who the child is since she had brain surgery. Owen assures Ethan that she’ll remember him, he just needs to let his mom heal.

April’s paramedic beau, Matthew, ended up in the ER after he failed to shield patients from the tanker explosion. Jackson tells April not to worry and insists he’ll check him out so she can get back to her patient, a pregnant woman who needs an OB-GYN consult – as soon as possible. Jason, Jo’s boyfriend, finally shows up after several pages, forcing Alex to give him a mouthful about his tardiness. The baby makes it out fine but his mother succumbs to her injuries shortly after. April learns that her patient and her husband were together when they were young, went their separate ways, but then got back together after reuniting on the same bowling team. This makes April question the universe and if people were really meant to be together. When she shares this with Matthew, he calms her down, comforting her by saying he’s going to be just fine. But was it Matthew she was really talking about?

Alex rants to Stephanie that Jo’s boyfriend is a jerk, to put it nicely. Stephanie lists off all the good things about him, which disgusts him. Alex really lets Jason have it when he denies to deliver the news to April’s patient’s husband, after Alex finds him smooching with Jo. Jason technically shouldn’t have to deliver the news (since he wasn’t the primary doctor on the case) but Alex gives him a hard time about it anyway. The two decide to exchange immature insults: “You’re a douche,” said Alex. “No, you’re a douche,” said Jason. “I guess I’ll be doing your job, again,” claimed Alex before he delivers the news to his patient’s husband.

Meredith and Jo’s patient’s initial scans were clean, so Meredith insists she’s going to run more tests, which also come back negative. Casey says she can’t ignore the gut feeling she has. Meredith is all set to discharge the patient until she finds out the strep test was a false positive. After reviewing the patient’s chart, she comes to the conclusion that he may have Kawasaki disease but she can’t confirm it until she sees his eyes. The patient’s eyes are red, which means Meredith is right. Casey made the right diagnosis after all, considering Kawasaki disease was one of the many diseases she had written down from her internet research. Mom’s just know!

Despite her best efforts, Callie doesn’t make it to the TED Conference. Arizona insists it’s a good thing because it gives her time to spice up her speech for next year, which Callie doesn’t appreciate. Richard and Arizona set up a station in the conference room so Callie can live stream her speech via satellite. She goes against her notes and speaks from the heart, talking about her rough year. “What holds us together when things fall apart?” So much for that public speaking phobia, Callie.

Cristina’s patient coded so she decided to do therapeutic hypothermia, which Owen criticizes her for. He later apologizes, admitting that she was operating on a little boy’s dad that he wanted to see live. Funny, Cristina doesn’t take orders from boys. Her words, not mine. Regardless of his difference of opinion, Cristina made the right call. Owen’s patient’s father is going to be just fine.

Later that night at Joe’s, Stephanie thanks Jackson for not being a “douche.” When everyone realizes Jo is missing, Alex responds that Jo is probably out “with assface.” But he’s not bitter, right? Meredith stays at the hospital to meet with Bailey because she wants her to map Zola. But the biggest – and scariest – request comes when Meredith asks to get mapped. She wants to know, once and for all, if she’s going to get Alzheimer’s.