The Chief and his team are detailed to escort a spy to Mexico, in order to make an exchange with the Russians for an American scientist. When Ironside and the spy are kidnapped by a Mexican political group, Ed has to keep the Russians at bay long enough to get the pair back, so that the exchange can be made.

A violin tutor at a conservatory in San Francisco is murdered, and the suspects include an eclectic mix of talented musicians. The only clue possessed by the Chief is a message sent by the dead man to one of his students, hidden in a collection of pieces of classical music.