A beaten and bloodied Jo says she was arguing with Jason when things got really bad. Alex lets her know that she's safe before rushing out the front door with a determined look on his face. A short time later, an unconscious Jason is in the hospital with a serious brain injury. Alex asks Derek to help save the guy from dying. That's not going to be easy. The damage is severe.
Derek deals with Heather's weirdness as they operate on Jason. They won't know how bad the damage is until he wakes up. In other news, Owen continues to watch over Ethan as the chances of the young boy's dad coming out of his coma grow steadily worse. Cristina notices a clot they missed in the patient. Derek steps up to fix the problem in a risky procedure. Heather must take over when he has to step away for an emergency. Cristina freaks out when she sees Mousey taking things home. Heather does good though.
Meredith approaches Jo, who is actually the one who hurt Jason. She lost it after he hit her. Meredith lets her know that she loves Alex and doesn't want him to take the fall for her. Jo assures her that she would never let him do that. After she leaves, Meredith trips and falls on the stairs. She fears she may have hurt the baby, but all is well after a quick checkup with the OB. Whew!
A hurricane-like storm is headed towards Seattle. Owen has everyone prepping for an emergency situation. Bailey volunteers to print and organize hard copies of all computerized patient files just in case there's a power loss. Shane is ordered to help her much to his chagrin. He'd rather scrub in on surgeries. That's something Bailey is looking to avoid at all costs. Richard believes she needs some tough love, so he orders her to get in the game or get out. At the end of the day, she opts to get back in the game.
Dr. Lauren Boswell (guest star Hilarie Burton) is the brilliant craniofacial specialist who has been flown in to help with an infant whose brain is growing on the outside. She's been working with (and flirting with) Arizona ever since she arrived. Jackson scrubs in on their surgery. He learns that Lauren has heard stories about the group of docs who bought the hospital to save the day, aka the Grey Sloan Seven. That's an actual thing. Arizona is extremely impressed with Lauren on many different levels.
April treats a construction worker who impaled himself on three pieces of rebar. Leah hopes the patient's name is Bob, as in shish ke-Bob. Sadly, his name is Leon. Owen wants to pull April off the case, but lets her work it after she argues. The docs need a powerful grinder saw to cut the rebar. Owen and Ben storm into the OR to stop them from using the power tool. The sparks mixed with the oxygen in the room would cause a major explosion and, well, that would be bad.
A team of docs work in harmony as they safely cut away the rebar in the combustible OR. April is making all the right calls, but Owen orders her away to prep for the storm. She's whisked off to an incoming trauma. The patient is having chest pains. Then he's dancing. Benny and Joon fans rejoice! The song "I'm Gonna Be (500 Miles)" echoes throughout the ambulance bay as a flash mob of dancing friends swarm the area. April has no idea what's happening as her smiling colleagues watch the action in the background.
Everyone is in on the musical spectacle taking place before April's eyes. The mastermind of this musical event, Matthew, takes center stage for the grand finale. He hands April a single red rose. He tells her that he knew that she was going to fall in love with her the moment he met her. Matthew gets down on one knee. He asks April to marry him. The answer is yes! Cheers erupt throughout the ambulance bay. Everyone is all smiles. As for April, her joy is also apparent though it seems to waver slightly when she locks eyes with Jackson.
Lauren asks Arizona to show her to an on-call room. She's a control freak who likes to stay close to her patients the first night after surgery. Arizona bids her an awkward goodbye just as the storm knocks out the lights. A hug turns into intense kisses. A rattled Arizona turns to leave when the lights come back on. Then she locks the door to the on-call room as she gives in to her passion. Elsewhere, Callie wonders where her wife could possibly be.
Jason awakens to ask for the police. Alex has a chat with him before the call is made. He convinces him that a guy who hits girls isn't the best person to be calling the cops in a situation like this. Alex returns home to let Jo know that he probably would have killed Chest Pecwell if she hadn't hurt him first. She wants to know why he would do that for her. Alex says, "Shut up. Why wouldn't I?" This emotional moment is cut short when the storm causes a tree to crash through the front window.
Owen gets the 411 from Meredith on how she knew Zola was meant for her. He's seriously thinking about taking care of Ethan full time. As it turns out, that won't be necessary. Ethan's dad comes out of his coma. He's going to be fine. Owen is happy and sad at the same time. Meredith clues in Cristina about his plan to take in Ethan. A short time later, she has to take a seat on a nearby bed. That's because her water just broke. Meredith Grey is having a baby!