1970. Inspector Kolbjørn Kristiansen, known as K2, witnesses a young woman desperately trying to catch a tram only to have the doors close before her face. The next time he sees her, she is dead - her body found between the tram tracks. It seems she has been shot . . .
As K2 begins to investigate, with the inestimable help of his precocious assistant Patricia, he discovers that the whole affair started two years earlier, when a group of politically active young people set out on a walking tour in Valdres. One night, it seems, the charismatic leader Falko Reinhardt vanished. This latest victim was Reinhardt's girlfriend.
It doesn't take K2 long to realise that to solve the present-day murder he must go back in time, perhaps further than 1968. But as he and Patricia begin to unravel the events behind this mystery, the detective fails to notice that his young assistant has her own problems to face. . .