There is a group called the Secret Seven and they want a mystery to solve or an adventure to discover.
There is a crooked old house in the snow and the secret seven get suspicious of the owner of that house.
The seven think that there is a prisoner in the house or is there?
I think that this is a really good book because it leaves loads of cliffhangers and questions which makes you want to read on! So if you like adventure and mystery stories then this is a great book for you!!!