Flick's big brother, Jack, goes missing in Peru and she is desperate to find him. But can she solve the greatest mystery of all: who Jack really is? A heartwarming, third novel from Waterstones Prize shortlisted author, Ewa Jozefkowicz, about the unbreakable bond between siblings.

Twelve-year-old Flick adores Jack and loves solving puzzles with him. But Jack is soon to flee the family nest and Flick worries she'll lose her partner in crime. During his gap year in Peru, tragedy strikes when an earthquake devastates the region and no one knows what has happened to Jack. Flick and her family are thrown into the horrible unknown.

She finds a key on a fine gold chain and a note with the initials SF in his room, and clings to the hope that SF (whoever that is) might hold the clue to finding her brother. When she sets out to uncover the identity of its owner, she meets new friends, rekindles a special relationship and discovers a whole new side to Jack. Intriguing clues from a legend about Inca gold, to a key with magical powers help her along the way.

Featuring a story within a story and a mystery to solve, The Key to Finding Jack, is about sacrifice and courage, the riches of family, friendship and the power of living life to the full.