Metal thieves attempt to steal copper from a railway line, only for one of them to be injured and taken to the ED - leaving the other two to cause an accident that derails a train. Among the passengers is a boy being packed off to boarding school and Tess, who must fight to save the youngster's life. But when she becomes trapped herself, Fletch makes a massive sacrifice to save her. Back at the hospital, Connie spends her first day as clinical lead, Ethan and Lily make up, and Cal is still in the doghouse