The Friendship Fairies – sisters Emme, Holly and Jess – are off on another adventure, spending the weekend in a mysterious old castle with their parents, while their mum is on a mission for work. The castle owner, Mr Jennings, is in a panic: ghosts are causing mischief, and there's a big wedding planned for the weekend! Can the Friendship Fairies come up with a plan to clear the castle of ghosts, in time to save the wedding?