A unique relationship between two women that transcends time and space.

Ale and her best friend Rubén, witness the brief sighting of a comet. She hangs on to the moment.

Spain, 1937. Ramón Mercader, a young communist combatant, is recruited and trained by the Soviet intelligence service to participate in a top secret mission ordered by the ruthless dictator Joseph Stalin: the assassination of his former political rival, Leon Trotsky, who is living in exile in Mexico.