When a night patrol spots a man fleeing and throwing a bag into the water, little do they know it is the first clue in a murder investigation. Around the same time, a woman is found dead in the city park, and divers soon recover the discarded bag containing a large sum of money belonging to the victim. Suspicion falls on one of her acquaintances, who admits to having argued with her—but insists he is innocent. Despite his motive and connection to the victim, he has a solid alibi, leaving investigators with a mystery to unravel.