This story follows the plot of the 2025 'I Know What You Did Last Summer' film. It is the 4th of July in the town of Southport. A year ago, Guest and their friends—Ava, Milo, Danica, and Teddy—were involved in a terrible incident that they swore to take to their graves. Now, their past has come back to haunt them. A mysterious figure in a fisherman's slicker is stalking the group, seemingly intent on making them pay for what they did. The friends must navigate their guilt, paranoia, and fraying relationships to survive the vengeful killer who knows their secret.