As Agatha and her companions board Olivia's yacht, they realize that they have been brought together for a macabre game. Olivia reveals that she has orchestrated a murder mystery weekend and one of them will be the victim. The guests are stunned but soon realize that they have no way off the yacht and must play along if they want to survive.
As the game progresses, tensions rise and secrets are revealed. Each guest has a motive for wanting one of the others dead, and Olivia seems to know more than she lets on. As they search for clues and try to solve the mystery, the guests begin to turn on each other.
Amidst the chaos, a real murder occurs, and the guests realize that they may not be playing a game after all. As they race to discover the killer before it's too late, they must also confront their own demons and past mistakes. In the end, only one will survive the deadly invitation.