Inspired by supposedly real-life sightings of UFOs in 1997 over Phoenix, Arizona, the science fiction film Phoenix Forgotten tells the story of three teens who go into the desert shortly after the incident, hoping to document the strange events occurring in their town, but then vanish. Now, on the twentieth anniversary of their disappearance, unseen footage has finally been discovered, chronicling the final hours of their fateful expedition.

Phoenix Forgotten is directed by Justin Barber and co-written by Barber and T.S. Nowlin. The film stars Florence Hartigan, Chelsea Lopez, Justin Matthews, and Luke Spencer Roberts. The producers of Phoenix Forgotten are Wes Ball, T.S. Nowlin, Mark Canton, Courtney Solomon, and Ridley Scott (director of both Alien and Blade Runner), who, we hardly need to point out, has probably forgotten more about crafting big-screen science fiction scares than most people will ever know.

Phoenix Forgotten arrives in theaters April 21. Watch the film’s trailer, premiering exclusively here, above.