Dreaming of a Prior World - S1.E6

The gang is on a train returning back to their hideout after successfully stealing the Clock of Magi. Tiger and his gang (including Angie who deceived Chiko into thinking she was her friend) all of Twenty Faces' gang is subsequently killed excluding Ken, Chiko, and Twenty Faces himself. In order to save Chiko from an explosion, Twenty Faces and Tiger supposedly die in an explosion. Ken runs off feeling betrayed, and Chiko is left in shock.