The murder of a prominent attorney is connected to one of his recent cases, in which a company was being sued for serious environmental damage. Martin Beck and Lena Klingström find evidence which brings new light to the investigation - but who's pulling the strings?

Martin Beck gets a phone call from his German colleague, Hans Sperling, who is in Stockholm to buy a painting at auction. Sperling has found a dead woman in his hotel, and needs Martin's help. The murder investigation leads them into a dark world of art fraud.