Barcelona, 1912-a city still recovering from the dramatic incidents of the so-called "Tragic Week" when Catalonian conscripts bound for the unpopular war in Spanish Morocco had rebelled at the city's dockside against the royalist forces. In the fighting, many were killed, and afterward, even more imprisoned, including an Englishman, who was later found dead in his cell.

The dead man had been a prominent businessman in Gibraltar, so what was he doing in Barcelona? And how did he really meet his end-murdered, in a prison cell? The case, in Gibraltar's view, cries out for investigation-and by someone independent of the Spanish authorities. So Scotland Yard dispatches Seymour of the Special Branch.