John Green is murdered while on the telephone to the district attorney. The obvious killer has a good alibi; the D.A. is then shot. As Philo Vance and District Attorney Markam were looking through the apartment of John Green who had been murdered the day before, Markham was shot. Both of their suspects, Mrs Green and a man named Edward Lee, have alibis for around eleven o'clock, the time they believe the murder of John Green was committed.