During the horse fair in Oxford, Billy got captured by the gobblers after running off in the middle of holding a horse-trader's horses and taken to Bolvangar. He stood guard with Roger Parslow while Lyra Silvertongue and Kaisa took advantage of a fire drill to release the dæmons who had been victims of intercision. He was reunited with his brother when the gyptians and witches liberated the children.
In the film The Golden Compass, Billy's character is fused with that of Tony Makarios. Billy and Roger Parslow are captured by Marisa Coulter and taken to Bolvangar. Billy has the dæmon named Ratter and he becomes a victim of intercision.