- Philo Vance, dilettante detective
- John F. X. Markham, district attorney
- Mrs. Tobias Greene, matriarch
- Julia Greene, eldest daughter
- Stella Greene, daughter
- Ada Greene, youngest daughter
- Chester Greene, eldest son
- Rex Greene, younger son
- Sproot, Greene family butler
- Gertrude Mannheim, cook
- Dr. Arthur Von Blon, family doctor
Locale: New York City
It seems an intruder to the Greene home has shot and killed Julia Greene, and wounded her sister Ada Greene. Their brother, Chester Greene, asks District Attorney John F. X. Markham to investigate personally, as he feels the routine police inquiry is inadequate. Markham invites Philo Vance to come along. The intruder entered and left the home without leaving a trace other than footprints in the snow outside. The question is why the intruder - if bent on burglary - even bothered to go upstairs where the family was sleeping, when the valuables were downstairs?
As soon as the investigation begins, two more murders follow .. Chester Greene and Rex Greene. Now it seems someone is trying to wipe out the Greene family, one by one.
This is a good diminishing-pool-of-potential-victims novel as the Greenes are eliminated one by one, with no apparent motive. As Van Dine novels go, not overly complex and Philo Vance stays relatively focused without wandering off into abstract monologues on irrelevant matters too often.
"This affair is too complicated to be untangled by the unravelling of details."
"The person who sat in that library night after night and read strange books by candlelight is the key to everything."
Philo Vance: "The intruder must have left the room."
Sibella Greene: "I suppose he must have, if he's not there now."