When Detective Chief Superintendent George Masters is attacked by a man with a syringe, he subsequently contracts Hepatitis B, putting him out of action for an extended period of time. The family travels to a remote village on the Cornish coast for a period of convalescence.
For awhile Masters is listless, with little interest in food or much else. Then one morning he is approached by five-year-old Oliver Holtby, who asks him, "Please would you find my Daddy for me?" It seems that James Holtby, Oliver's father, had gone to Exeter for a job interview a few days before but had not returned.
Masters is re-energized by Oliver's request. After he calls Scotland Yard to ask about James Holtby, he is immediately contacted by his colleague Bill Green. It seems that James Holtby is the key witness in a case of bank robbery and murder that Green has been investigating. With Masters back in limited action, the old team is reunited.
This is one of my favorite entries in the series. The meaning of the title isn't revealed until the final chapter.