A rigid man of fifty leads a solitary, apparently respectable life, as clerk and bookkeeper for a small business and part-time rent collector for his landlord.

The tenuous mental equilibrium he has been able to maintain is threatened when a young man, healthy in mind and body, a doctoral candidate in psychology, who has the same name, becomes a roomer in the house.

Danger the older man senses from the moment the new tenant appears is horribly realized for him when children use the mannequin as the figure in the bonfire at the Guy Fawkes Night celebration.

The major irony is that an aggressively normal research graduate is writing a thesis on criminal psychopathy, sharing his surname and lodgings with a repressed psychopath; and his innocent, well-meant action forces the strangler out onto the streets in search of real victims again.

The lodging house also contains a series of individuals or couples engaged in ironically paralleled marital, sexual and social relationships that often appear exploitative, inadequate or shabby.