McNair House is a charitable institution, set up to care for cathypnic children. With their incredibly slow metabolisms, cathypnic kids are irresistibly plump little dumplings, inspiring a near-obsessive devotion in their caretakers. Jimmy Pibble, newly laid off from Scotland Yard, has dropped by the McNair purely in a private capacity, but if he's surprised to find his own passions being stirred by the children, he's even more surprised at the signals he's getting from his old detective instincts. He knows that cathypnia is more than chubby cheeks, that the disorder has a dark side. He's slowly coming to understand, however, that the devotion does as well.