Five Get into a Fix (English, Paperback, Enid Blyton)

The Famous Five are ski-ing and having a brilliant time! But there’s always a mystery to solve: such as who is living in the mysterious house near their chalet? The caretaker says the house is empty…but the Five have seen a terrified face at the window…

One thing’s for sure — they have to get to the truth!
Source- goodreads.com