When dozens of critical patients flood the ER, Robby and his team struggle to keep up amid quickly diminished supplies.

As the night shift begins, Robby refuses to give up on a mass casualty victim. Samira and Santos each attempt risky moves.

While Robby struggles with a loss, Abbott coaches Samira through a risky procedure, and Mel treats a teen with a mysterious rash.

Robby resorts to unorthodox methods to convince a father to allow treatment for his son. Later, Whitaker tracks down a missing patient.