The sergeant of the Civil Guard Bevilaqua and his assistant, Corporal Chamorro entrust them with the task of reactivating the investigation of the death of Ivan, a crazy young man, who happened on the island of La Gomera three years ago.
A meeting in a London bus with jewel thief Lady Christina takes a turn for the worst for the Doctor when the bus takes a detour to a desert-like planet, where the deadly Swarm awaits.