This film is Joseph Losey's mood piece that delves into the psychological makeup of Frank Jackson (Alain Delon), the assassin of exiled Russian Communist leader Leon Trotsky (Richard Burton). The tale chronicles the final few months of Trotsky's life, from the May 1940 raid upon Trotsky's Mexican compound until August of that year when Jackson's assassination attempt succeeded. Much of the film details how the shy and mysterious Jackson gained access to the compound through ingratiating himself with family friend Sylvia Ageloff (Romy Schneider). The reclusive Trotsky, seeing a part of himself in Jackson, begins to warm up to him, never realizing that Jackson will be the man to finally kill him.