Arthur's parents have been married for 10 years and it's time to celebrate. But the festivities are cut short when the van breaks down, stranding the whole family. After watching a classic horror movie, Arthur and his friends are scared to step out into the playground. With help from Persimmony Glitchet, the mysterious author of the book series Horrendously horrible happenings, Fern learns that creativity, imagination and hard work are the real ingredients for a good tale.