Billy battles to save his little sister from the Barglebogle - a monster who arrives at the same time as the new baby, and seems to want to take her away...

When Billy's Mum has a baby, a new sister isn't the only strange thing to come into Billy's house. There is also the mysterious monster, the Barglebogle, who is even more disruptive than a new baby. Billy is not happy about either of them but once he sees that the Barglebogle is out to get his sister, he is determined to save her.