Drinking outside a canalside bar on a perfect summer's evening, Lotte is witness to the fatal stabbing of Piotr Mazur, a Polish security guard working in one of the city's department stores. And as Lotte starts to investigate Mazur's death she keeps finding facts that potentially link him to the case of the dead tourists - but soon realises that the head of the team investigating their murders is trying to bury the information just as quickly as she unearths it. Lotte saw the victim in the bar moments before he was killed, and he was with a woman who passed him a photo of a child. She is now convinced that his death wasn't a revenge-killing over drugs after all, but she has to think carefully about what to do for the best, especially as key evidence in Mazur's murder comes from someone she knows she cannot trust.