To reduce his blood pressure after a heart attack, a man begins killing the people who are stressing him out.

After suffering a violent heart attack, Bill is advised by his doctor to lower his blood pressure by eliminating the stresses from his life. Taking his doctor's advice literally, Bill starts killing everyday people who irritate him with poisoned darts. The killings lower Bill's blood pressure for a while but attract the attention of Detective Jordan, an enigmatic cop who plays a strange cat and mouse game with Bill as he tries to decide whether he should arrest him or join him in his campaign. As the cop begins to make Bill's life a living hell, stresses closer to home ramp up his blood pressure, and Bill puts his best friend Stan's ex-wife on his hit list. Convinced that their friendship won't last until Stan's ex- is dead, the two men concoct a plan to get rid of her that will look like a heart attack. Although they get away with the murder, anomalies in the forensic report suggest that the ex- was poisoned. Suspecting a connection between the the "Dartman" and the poisoned woman, Detective Jordan manufactures a crazy scheme to flush Bill out as the killer he's looking for. With his blood pressure at an all-time high, Bill is forced to endure Jordan's insanity as he works to extract himself and Stan from the investigation. Now targeting his own wife and her lover, Bill takes drastic measures to derail Jordan, stay out of jail, and maintain both his physical and mental health. Bill's calculated attempt to frame another man for the dart killings forces detective Jordan to face the truth and confront his own demons.