When the hospital is inundated with bus crash victims during a winter storm, Emily is assigned to run triage in the E.R. During the chaos, Emily is forced to do an emergency skull procedure on a heroic Marine who suddenly collapses. Tyra bristles at her father’s lack of respect for her as a doctor, but they later experiences a breakthrough when they perform an emergency c-section together. Meanwhile, Will and Emily secretly work to help an unexpected patient leaving Cassandra to question Will’s true feelings for Emily. Micah finally makes a bold decision in his personal life.

Season Finale: Emily's decision about starting a relationship with Micah becomes even more complicated when Will hears about it and begins to feel jealous. Emily and Tyra treat an unruly woman, but after learning of her home hoarding situation, Emily wonders if the woman's personality changes may be caused by her many cats. Now that Cassandra and Will have broken up, Cassandra's strictly professional behavior distracts Will and causes him to misdiagnose their patient. Meanwhile, Micah's sister comes to town after finding out the truth about their mother.