Anton Narinskiy

After several of Bailey's patients die, she becomes the focus of a CDC investigation; Cristina teases Alex about his feelings for Jo; Owen continues to take care of Ethan while his parents remain in the hospital.

The 126 race into action when a major train derailment causes multiple injuries; Tommy makes a bold move in her relationship with Trevor; Wyatt asks Owen to give Judd his job back.

The 126 race to contain a toxic chlorine cloud of death unleashed by the train derailment; Owen names the station's new lieutenant.

Three seperate murders have taken place in Austin, Texas. The victims are two young women, and one young man. They were all seen for the last time at different but large social gatherings.