Ross is a successful, happily married cardiac consultant - until his wife Fay announces she has fallen in love with the notorious womanizer Julian Kane. Later, Ross's assistant discovers two phials missing of Zarabell Four, a drug potentially lethal to cardiac patients. When Julian dies from a heart attack, all fingers point to Ross. But as the play progresses many enemies of the deceased are revealed and audiences will guess right up to the final moments of this well-wrought thriller.