Like “Happy Death Day,” “Palm Springs,” and “Lucky,” Christopher Smith’s “Triangle” is a time loop movie, where Jess has seemingly been living out the same boat ride over and over again. However, the film focuses on a single run of the loop, rather than a series of days with differing outcomes. The loop starts with Jess yelling at her son Tommy before being distracted by the ringing of her doorbell. She goes to investigate, but no one is there. Jess later gets in a car and arrives to get on a boat, explaining to her friend Greg (Michael Dorman) that Tommy is now at a special school for children with autism and will not be attending the trip.
While aboard, a storm is approaching, and Greg picks up a distress signal from a woman claiming that someone is killing everyone on board, but they are unable to get her location. The storm eventually capsizes Greg’s boat, forcing the survivors to board a seemingly deserted passing ocean liner called Aeolus. Jess feels an extreme sensation of déjà vu as they explore the ship, eventually spotting someone watching them, and Greg’s friend Victor (Liam Hemsworth) chases them down.
Jess returns to the dining room and notices the food from earlier is now rotting. Victor, returns, covered in blood, and tries to kill Jess. Gunfire is heard and Jess finds Gred dead, with passengers Sally (Rachael Carpani) and Downey (Henry Nixon) claiming that Jess is the one who shot him. Suddenly a masked shooter appears and kills them, chasing down Jess. This is where the loop converges, as Jess realizes that she is the masked killer, and there are at least two other versions of herself on board, and several versions of everyone else as well. It seems as if the loop restarts once everyone on board is killed. At least, that’s Jess’ theory.