Everyone is gathering nuts and berries to store for the long winter months ahead. Adventurous Evie has heard of a long-forgotten hazel grove which has lots of nuts. She persuades her three friends to go in search of the grove, but on their way they get caught in a storm. Seeking shelter, they stumble across a hollowed-out tree. Evie realizes this could make the perfect hidden den for a sleepover. But will the den remain a secret for long?