Who is Barty Boar? Nobody knows the true identity of Barton Vale FCs infamous mascot. Archie Carr, 11-year-old son of star striker Gavin Carr, is determined to de-mask him, and when he does an unlikely friendship begins leading them into a series of misadventures with hilarious results, especially when Barty is given a new sidekick - the enchanting Betsy Boar, whom he hates on sight! Meanwhile, Archie's twin sister Rosie is fighting for her place in the boys' football team, when she discovers that fellow midfielder Kieran Gregg is a budding goalkeeper. No one can find out, least of all Kieran's football star dad, who is dead against his son playing between the sticks! And what is it that lurks beneath Barton Hall School? Something scary enough to bring in a team of television ghost hunters. It's an opportunity Archie can't miss, and with his usual daring, decides to join in the ghost hunt uninvited and gets the shock of his life!