On Second Great Fire of London, during the The Blitz, an elderly Dr. John Watson tells his nurse the tale of an unrecorded case he shared with his friend Sherlock Holmes. On May 19 1882, a royal treasury ship is destroyed by a monstrous giant octopus on the coast of Newhaven, East Sussex. Holmes and Watson investigate the shipwreck and do not believe the first-hand accounts of the sole survivor of the attack, but nonetheless investigate. Inspector Lestrade states that he has recently had contact with Holmes's estranged brother Thorpe, a former partner of Lestrade's who was paralyzed during a bank robbery seven years prior.