Через год после смерти брата-близнеца Лиллиан в компании друзей возвращается в свой лесной дом рядом с озером. Почти сразу же девушку начинают преследовать жуткие видения, а вскоре и остальные замечают, что происходит нечто странное. Кроме того, местная легенда гласит, что это озеро может свести с ума.
Two traffic officers on a quiet morning shift try to stop a car for speeding. When the car finally pulls over, the driver gets out and shoots at them, killing one of the officers in cold blood. A national alert is issued and an extensive search for the ruthless killer begins, with the Beck group at the lead. Neither the officer’s shocked and wounded colleague nor any of the witnesses have seen anything helpful to the police. Finally, they find the car registration number using a surveillance camera. But, when they enter the car owner’s apartment, they find him shot to death. The first day of summer is a long one for the Beck group, as the killer has more victims on his list.
Spring is in the air and Puck and Einar, as well as Christer Wijk are invited to a wedding in Skoga. The day before the wedding, the bride-to-be enters a flower-shop in order to inspect her bridal bouquet of lily of the valley, but suddenly vanishes without at trace. When she eventually turns up again, it is Christer who finds her. She lies dead outside her home with a bouquet of lily of the valley in her hand. Everybody close to the bride are suspects, not least her best friend, whom Christer has just begun flirting with. Everybody seems to have something to hide. Question is: are their secrets connected to the murder?