Knock Knock

In this gripping #1 international bestseller, police inspector Ewert Grens must confront the haunting legacy of a brutal murder case from seventeen years ago, where the sole survivor—a five-year-old girl—was placed in witness protection. When a break-in occurs at the crime scene, Grens fears for the girl's safety and races against time to find her. Meanwhile, former informant Piet Hoffman faces a deadly threat to his family as he navigates a perilous criminal underworld, leading to a dangerous intersection of their fates in a web of secrets and conspiracies.