Gwen returns from holiday to discover a stranger named Adam Smith in the Hub. The rest of Torchwood is baffled by her reaction: Adam has been their teammate for three years. And, when Adam touches Gwen on the shoulder, she suddenly remembers him too. Indeed, the creature calling itself Adam has established himself as Jack's confidante and Tosh's lover. But his interference causes Gwen to forget her relationship with Rhys, while Jack is haunted by his distant childhood and his lost brother Gray. When Ianto realises the truth, Adam demonstrates that memories can be used not just to manipulate -- but also to destroy.