In the midst of the early days of the COVID-19 pandemic, Grey Sloan Memorial and its surgeons' lives have been turned upside down. It's all-hands-on-deck as Meredith, Bailey and the rest of the Grey Sloan doctors find themselves on the frontlines of a new era. Meanwhile, an unintentionally started fire has first responders from Station 19 bringing patients into the hospital for treatment.

Bailey finds herself in the middle of an argument with patients' families as they await news about their children who were injured in a fire. Winston surprises Maggie, and Amelia and Link try to have some fun as new parents. Teddy learns her colleagues know more than she may like about her relationship woes with Owen, and Richard and Koracick go at it.

The Grey Sloan doctors continue to face their new COVID-19 reality and deal with a familiar and stubborn patient. Koracick is put in charge of the interns who recently joined the hospital ranks and Link operates on a sex therapist. Elsewhere, Maggie finds comfort in Winston's virtual presence.

Owen faces a medical diagnosis that challenges more than he imagined. Koracick begins to go stir crazy. Maggie gets a not-so-subtle glimpse into Winston's background.

Bailey panics as she hears there has been a surge of COVID-19 cases, knowing she has loved ones in an assisted living facility. Meanwhile, Jackson and Richard team up against Catherine to teach her a lesson, and Teddy continues to try to mend her frayed relationships. After an intense surgery, Jo is uncertain about her future.

Grey Sloan Memorial faces new pressures as Seattle Pres is overloaded, and Grey Sloan Memorial is now on surge capacity protocol. Meanwhile, Owen and Amelia are faced with one of the most controversial surgeries of their careers.

Part 2 of a crossover with Station 19. The doctors are joined by the team from Station 19 as they tend to a tense situation with a lot at stake. Jo convinces Hayes to bend the rules on a case. Maggie and Winston reconnect. The crossover starts on Station 19 S04E06: Train in Vain (1).

As traumas and pressure mount, Grey Sloan doctors try to find a path forward; Maggie gives Winston hospital privileges and they work together to treat an uneasy patient; Jo, Link and Jackson play an unconventional drinking game.

After a heart-wrenching loss, Teddy struggles to cope and it triggers memories of her past; Amelia tries to help the situation by encouraging Owen to accept and forgive Teddy.

The hospital ventilator shortage has the doctors gravely concerned; Hayes' high-risk sister-in-law with multiple sclerosis ends up in the hospital with a kidney stone.

The Grey Sloan doctors are stuck in the middle of a fight between a newlywed couple who are injured in a car accident and brought to the hospital for treatment. Meanwhile, Jackson's generosity with COVID-positive patients goes a bit too far, and Hayes works to rebuild Maggie's confidence and convince her to perform an extremely risky heart surgery. The crossover started on Station 19 S04E10 Save Yourself.

Maggie is preoccupied with Winston while trying to treat a patient wounded in the Seattle protests. Meanwhile, Levi is tested by an emergency, and the doctors struggle to treat a patient who doesn't believe in COVID.

Amidst the need for more surgeons, Jo tries to convince Bailey to let her switch specialties. Elsewhere, Link accuses Amelia of overstepping while he is treating a patient remotely, and Winston comes up with an out-of-the-box idea.

Jackson pays a visit to his father that helps set him on the right path.

Jackson shares his big news with his colleagues while Koracick and Levi fight to save a pregnant woman's grandfather as she goes into labor. Maggie keeps a watchful eye on Meredith as Bailey and Richard put off telling her about DeLuca.

Levi gets accepted into the vaccine trial. Amelia and Owen treat a car crash patient. Hayes and Jo are met with Luna's legal guardian.

It's wedding day for Maggie and Winston. Meanwhile, Meredith takes on a new role at the hospital, and Jo makes a life-changing decision.