A Viking Mystery #1: Riddle of the Runes by Janina Ramirez (author) (UK edition)

Alva rushes through the trees in the dead of night with her sniffer wolf, Fen. Being out alone when there’s a kidnapper on the loose is reckless, but if she ever wants to be an investigator like her Uncle Magnus, she’ll need to be first to the crime scene. But what Alva discovers raises more questions than it answers, drawing her into a dangerous search for truth, and for treasure.