 Jack, Owen and Gwen pursue a man through the Cardiff streets, while Toshiko tracks his alien energy signature through the CCTV network.Gwen separates from the group, chasing down the suspect into a train station, and is able to grab the man's jacket but he gets out of it and runs away.Gwen discovers an alien device in the jacket pocket, and when she activates it, she finds herself seeing a brief vision of the past, of a lost boy wandering the train station.