This exciting mystery story will keep readers gripped, as brothers Joe and Carl quickly realise it's not always best to keep what you find. Written by Alan Durant.

• Collins Big Cat Progress books are specifically designed for children at Key Stage 2 who have a Key Stage 1 reading level, giving them age-appropriate texts that they can read, building their confidence and fostering positive attitudes towards reading.
• Text type: A mystery story
• Curriculum links: P.E.