Luke is going for a sleepover at Clyde's house whilst Sarah Jane goes away for the weekend, during which Clyde's estranged father Paul turns up hoping to get to know his son. Meanwhile Rani discovers that one of her classmates is in possession of a strange locket, that can be used to control people.

With Clyde's father Paul possessed by the alien pendant, he takes Clyde off for some fun. With a little help from some old friends, Rani and Luke try and track them down, leading to a waterside confrontation with the Berserker