Private detective Stas Severin is commissioned by an old friend to find his wife’s killer. From his client’s disjointed explanations, Stas realises that the case revolves around the substantial inheritance of the renowned antiques collector Arefiev, with the claimants to the estate forming the circle of suspects. A mysterious key, handed over to the detective, should help solve the mystery. The widower does not have time to say more: the next day, he dies in strange circumstances. Now Stas is drawn into this web of mysterious events not just in his professional capacity: he cannot let his friend’s murder go unpunished, and one of the heirs to the wealthy collector turns out to be his beloved…