The Secret Seven are siblings Peter and Janet, and Jack, Barbara, Pam, Colin and George. Together they are The Secret Seven - ready to solve any mystery, any time - in Enid Blyton's classic series of 15 mystery novels.

In book three, the Secret Seven have a new meeting place - a treehouse! But someone else is using it too. The gang are furious, but then they learn the intruder is in big trouble and needs their help.

Can the Seven come to the rescue?

First published in 1951, this edition contains the original text and is unillustrated.