Secret Seven Mystery

The Secret Seven are Peter and his sister Janet, Jack, Colin, George, Pam and Barbara. They meet every holiday in the shed at the bottom of Peter and Janet's garden - and solve mysteries, and eat lots of delicious food. But no one can enter the shed without whispering the secret password! There are 15 Secret Seven novels, and a collection of short stories.
A girl has mysteriously run away from home, and her parents are frantic with worry.
Can the Secret Seven follow the clues and catch up with the girl - or will Susie, Jack's troublesome little sister, get in the way
Each book features rarely seen bonus Blyton: extra stories, a quiz, additional artwork and insights into Blyton's life and writing process.