Trip to Bangkok, Coffin included(Viaje a Bangkok, ataúd incluido)

The colonel Daniel Blimp, of the secret British service, travels to Bangkok to investigate the murder of the Brittish Ambassador happened during a holiday in his residence. Blimp receives the help of Keats, agent of the secret service. Both men discover that the man who shot against the Ambassador is blind, and it takes the black skin as a result of a strange phenomenon of mutation.