While on vacation after a sensitive military operation, soldier Si-jin senses a connection with Mo-yeon, a beautiful and strong-willed surgeon.

Mo-yeon is embarrassed after her unintentional confession, but Si-jin isn't about to let her off the hook. Meanwhile, a visitor makes everyone nervous.

Mo-yeon and Myung-ju learn that not everything is what it seems. Meanwhile, a promotion is cause for celebration, and a trip reignites old passions.

Si-jin and Alpha Team join Mo-yeon and the doctors in Urk. Meanwhile, Myung-ju doesn't like how her father, Lt. Gen. Yoon, treats Dae-young.

Si-jin and Dae-young engage in a perilous operation in Afghanistan, while Mo-yeon assists in surgery. Later, Si-jin and Mo-yeon take in a movie.

Tempers flare over a dying man when Mo-yeon insists she can save the patient's life. Meanwhile, Dae-young and Myung-ju reunite at the airport.

The medical team returns to their regular lives, but something's off. Meanwhile, Mo-yeon makes a bold career move, and Dae-young faces a tough choice.

After sharing a moment, Mo-yeon isn't sure what to think about her relationship with Si-jin. Later, Si-jin receives a panicked phone call.

Dae-young is rattled after seeing an old nemesis, Mo-yeon shares a dark dinner with Si-jin, and an unusual package arrives from home.

While Dae-young and Myung-ju remain quarantined, the rest of the team fights the epidemic. Meanwhile, the supply truck with the cure disappears.

Dae-young has a bad feeling about Si-jin's solo mission into Agus's hideout. Mo-yeon wonders if she's capable of dealing with Si-jin's secrecy.

After a patient is rushed to the hospital, Mo-yeon is shocked to see who is in need of care. Meanwhile, a microchip reveals unexpected information.

Si-jin and Mo-yeon spend some much deserved time together. Dae-young and Myung-ju continue to have communication problems. Devastating news arrives.

After a powerful earthquake strikes Urk, the country descends into chaos. It's up to the medical team and soldiers to search for survivors.

In the earthquake's aftermath, heartbreaking decisions must be made by Si-jin and Mo-yeon, who both strive to save as many people as possible.

When an aftershock strikes, Mo-yeon sees firsthand just how dangerous Si-jin's job can be. Later, an old phone message is accidentally broadcast.