Crime writer Erica Falck is shocked to discover an old Nazi medal among her late mother's belongings.

Inspired to dig deep into her past, she visits a retired history teacher for answers. Two days later, he’s dead. Detective Patrik Hedström is on paternity leave.

But his wife’s enquiries appear to have set off a chain of murders and he’s finding it hard to keep out of the investigation. A terrible secret from the darkest days of World War II is coming to light – and their families’ histories are right at the heart of it.