Psychiatrist-sleuth Dr Basil Willing is in a tobacconist's in Manhattan when another customer follows him into the shop, buys cigarettes, and leaves in a hurry. The man hails a taxi to take him to 51st street with the instruction: 'Come back and call for me; I am Dr Basil Willing.'

Intrigued, the real Basil Willing hails a second taxi and finds himself at a formal dinner party given by a psychiatrist for his patients, who do not really seem at ease there - and later he discovers the horrifying reason why ...