While on their helicopter flight rotation, Mark and Susan find an injured family of four who they bring to the ER.

The ER docs tend to three teenagers who were in an accident on the way to their senior prom. Greene and Carter treat the most severely injured, a boy suffering from third degree burns over 80% of his body. Benton receives the ER trauma fellowship. Carol finally tells Doug about her pregnancy; Kerry also figures it out. Mark and Elizabeth draw closer. Lucy tells Carter about her Ritalin addiction. "FBI agents" bring in a shot stripper.

Weaver tries to save the life of a rape victim while Corday struggles with feelings of disdain as she is forced to save the rapist. Cleo treats a teenage alcoholic boy whose alcoholic mother refuses to recognize her problem or his.

As the result of a school shooting, Kovac and Benton care for the gunman and his victims. Abby discovers that Carter has been illegally injecting pain relievers. Greene and Weaver confront Carter about his problem, and Weaver orders him to enter a drug rehabilitation center or leave the hospital permanently.

In the series' 150th episode, a massive train wreck mobilizes the emergency room doctors. Corday, Carter and Kovac rush to the scene. Corday falls and injures her back, bringing on contractions in only her 25th week of pregnancy. While amputating the legs of a fallen firefighter, Corday stops because of her pain.