Stefan Veliko, a young Russian pianist, is making his concert debut in London. However, he is being used as a pawn in a game to wreck Anglo-Soviet relationships. First a young woman is found dead in his apartment, which is exploited to blackmail him into killing a delegate during a piano recital. Fortunately, he has the Avengers on his side, although it is a close call for Mrs. Gale.
—don @ minifie-1