When the COVID-19 pandemic hits Seattle, the Station 19 crew leans on each other for support, on the season premiere.
When Riley is asked to the semi-formal by a classmate named Charlie, she must choose between him and Lucas; Cory's brother, Eric, runs into an old friend.
Things get out of hand when Mickey and Jimmy throw a Halloween party in the burned out remains of the mansion; Sabrina seeks to repair her tarnished legacy; Mickey teaches some pranksters a lesson.
The CSIs investigate a present-day crime with ties to a mob heist that occurred 25 years ago. Meanwhile, Brass has a decision to make when his daughter attempts suicide.
An unintentionally started fire has first responders from Station 19 bringing patients into the hospital for treatment; Amelia and Link try to have some fun as new parents.