Look Out, Secret Seven (Secret Seven #14)

A little strange, for Peter-–being head of the Secret Seven–-usually likes to be involved right from the start! It's arranged that the Seven stake out the woods that night, waiting for Tom Smith to arrive, as the Seven have worked out that the thief is the only one who can get the medals from the hole in the tree trunk, and Tom Smith will be going along to wait for him to turn up.