The Endless (2017)

Brothers Justin and Aaron Smith receive a video cassette from Camp Arcadia, a group they belonged to as young children. The pair's recollection of events differ; while Aaron recalls them as a harmless and friendly commune, Justin thinks the group was a UFO death cult. Aaron points out that the video cassette proves the members are still alive. Justin, however, is worried that talk of "ascension" may be a code for some future mass suicide. Fed up with their inability to make friends or find good jobs since leaving Camp Arcadia, Aaron and Justin decide to return for just one day.

They head to Camp Arcadia in the backwoods outside of San Diego and receive a friendly welcome. None of the members seem to have aged in the decade since their departure. Among them, Anna and Lizzy take an interest in Aaron and Justin, respectively. While Aaron welcomes the attention, Justin keeps his distance. One of the members, Hal, excitedly shows Justin a physics equation he has been working on. He says that he cannot explain what it represents, as it would be akin to describing an impossible color. However, he hopes that Justin will eventually accept the group's beliefs now that he is older. As they participate in various activities, Aaron grows increasingly fond of the camp, and convinces Justin to stay an additional day.

During one activity, members attempt to win a tug-of-war against a rope that ascends into the night sky. Justin says it is held by a member on a ladder but cannot explain how he loses when everyone else is present. The brothers separately notice increasingly abnormal occurrences. While exploring the woods, Justin becomes convinced an invisible entity is observing him, and it leaves him a photograph of a buoy. When pressed for answers, Hal admits to Justin that he knows no more than anyone else. His equation is his interpretation of what is happening, and he encourages Justin to find his own answers by following the entity's clues, such as the buoy in the photograph. Two moons rise in the sky and Hal explains away the second moon as an atmospheric phenomenon, then says that two moons bring the truth, and three moons signify the ascension. Hal tells Justin to come to a conclusion before a third moon rises.

On a fishing trip with Aaron, Justin sees the buoy from the photograph and dives under it. He returns with a toolbox containing a tape and says something else is under the water. Disturbed by the strange events and hints of their meaning, Justin insists they leave immediately. At the camp, Hal and Justin get into an argument after Hal plays the tape, which is a recording of Justin and Aaron misrepresenting Camp Arcadia to outsiders. Justin calls Hal a cult leader, and Hal says Justin made up lurid stories to tell the press about Camp Arcadia. Outraged that Justin was misleading him, too, Aaron refuses to leave. Justin's car does not start, and he leaves to find help.

Justin encounters several people stuck in time loops, most of whom repeatedly experience violent deaths for the entity's amusement. They explain that Justin will also become trapped once the third moon rises. Justin finds Aaron, and on their way back to the camp, the brothers pass various monoliths and structures depicting the entity as interpreted by different cultures. Despite Justin's explanations, Aaron still prefers staying to returning to his old life. He reasons that in Camp Arcadia he can live forever with people who care about him. Although each time loop culminates with death at the hands of the entity (considered a sacred ritual by the cult) he says that is still better than a dreary life of menial jobs and no friends. When Justin admits he was wrong to force Aaron into always following his lead, Aaron becomes hopeful that their relationship can improve and agrees to leave after all. The brothers barely escape as the entity appears to destroy the camp. The brothers drive away while the loop resets, and the reborn members of the cult seem wistful about their departure.