A high-risk lung transplant pushes the surgical team to their limits. Meanwhile, Bailey juggles a trauma patient whose treatment hangs in the balance.

It's all hands on deck at Grey Sloan when a group of medical students is injured by a floor collapsing at their white coat party. Jo and Link are forced to talk about the future, while Jules confronts Winston about his attitude.

An explosive case arrives at the O.R. that might endanger all the lives of the people working there, which leads Dr. Burke to declare a "Code Black" for the hospital. Bailey worries where her husband is as she is in labor. Also Izzie and Alex may be creating some heat.

Derek is still operating when he finds out about Meredith's current situation. Meredith is freaking out about her situation. Webber and Bailey are dealing with medical health issues. Cristina and Izzie have their own issues to deal with because of Meredith's situation. Addison freaks out when George tries to find a solution to Bailey's impromtu postponement. Overall, Seattle Grace Hospital is still under code black and the situation is getting worse.

Dr. Arizona Robbins returns to Grey Sloan for a particularly complicated case. The interns are interrogated about their past mistakes, while Teddy is eager to return to work after her health scare.

The aftermath of the convenience store shooting brings chaos to Grey Sloan. Ben hits a wall with his new emergency preparedness plan. Romantic tensions surface for Owen, while Amelia and Winston disagree over the surgical plan for a young patient.

This episode is the second part of a two-hour season finale. Richard tries to get information from Addison about a family member's condition. Callie and George have a talk about his feelings. Meredith and Derek have a talk about Doc.

When a trauma patient arrives at Grey Sloan, it forces Jo to confront her past. Meanwhile, Bailey and Ben have to talk to Tuck about dating.

On the heels of life-changing news, a thunderstorm hits Grey Sloan. The attending surgeons and interns work together to save an injured reporter and family affected by the storm. Meanwhile, a beloved author undergoes a risky surgery, and complications from the storm arise.

Meredith and Nick return to Grey Sloan to treat a liver transplant patient. Meanwhile, Bailey hosts an intern retreat at her home, and Winston and Ben aid an unexpected crash victim.

Following a difficult case, the team faces the complexities of medical ethics. Meanwhile, Bailey continues to navigate her working relationship with Ben, while a group of college students on a scavenger hunt causes chaos around the hospital.

Seattle Grace Hospital is hit with a crisis like no other in its' history.

Train Wreck victims come to Seattle Grace and all staff gets called in. Everyone deals with really weird cases. Except Addison and Izzie. They work with a woman who is pregnant.

George and Derek work together, Denny still doesn't have a heart, and Meredith gets paired with Callie. A 12-week pregnant girl dies in the O.R. and her parents try to keep the baby alive. This causes tension between Derek and Addison. One doctor's overreaction unites two bickering patients. Finn is still treating Doc for medical problems.

Denny needs a heart or else. Izzie and George go crazy trying to get him one. Derek has the life of a friend in his hands as he operates on Burke who has been shot. Burke cannot operate on Denny after Denny's heart stopped and now Denny is in a dire condition. Cristina gets put in charge of the ER and she is worried about Burke.

Meredith and Amelia work to secure funds for their research while Amelia finds herself at odds with a new attending. Levi runs into someone from his past, and Owen gives Winston advice. Lucas ditches Mika, forcing her to treat a patient alone.

After firing some of Grey Sloan's best, Catherine continues to interfere with Meredith and Amelia's research. Accidents at a climate change protest bring unique cases to the hospital, and Bailey encounters a blast from the past.

Simone and Lucas work to balance their relationship while competing to assist on an awake kidney transplant. Teddy offers Amelia a new opportunity, and Ben's interview doesn't go as planned. Meredith's secret causes tension with Richard.

Mika struggles with a life-altering personal matter. Meanwhile, Bailey and Ben navigate their personal and professional roles, while Levi finds a connection in an unlikely place. Jo and Link get surprising news.

During a high-stress day at Grey Sloan Memorial, the fates of a patient in critical condition and a helicopter-bound medical team hang in the balance. Teddy and Owen work on their marriage, while Bailey, Blue and Link treat a hospital employee.

Teddy and Owen plan a date night that gets derailed in more ways than one, while Jo struggles to do it all at home. Mika adds more to her plate to make up for taking time off to be with her sister, and Levi is faced with a monumental decision.

The doctors at Grey Sloan must put aside their emotions under intense circumstances. Levi asks James a shocking question that could impact their future.

In the midst of a deadly heat wave, the team at Grey Sloan struggles to keep up with an overwhelming amount of patients. Amelia and Winston face a challenging surgery, while Jo and Lucas run an errand for the hospital that takes an unexpected turn.

Meredith and Amelia prepare a funding proposal for their Alzheimer’s research. Meanwhile, Teddy and Owen hit a breaking point in their marriage, while Jules has an awkward encounter with Dr. Beltran.

Amelia and Simone attempt to perform a high-stakes and groundbreaking brain surgery. Teddy and Bailey attend a medical conference and run into Dr. Cass Beckman. Meanwhile, Jo struggles with her irritation toward a younger OB-GYN.