The film begins with nostalgic video footage from a little girl’s birthday celebration in Phoenix, Arizona, captured by Josh Bishop (Luke Spencer Roberts). It’s his younger sister Sophie’s sixth birthday, and he roams around, asking guests to record messages for her future self. While recording, his grandfather shares some cringe-worthy advice about obedience in marriage, prompting Josh to quickly change the subject. After capturing a heartfelt message from their mother, she flips the camera around, urging Josh to say something sweet to Sophie. Overtly uncomfortable in front of the camera, Josh fumbles through his words. Suddenly, laughter and wonder erupt from the guests, pulling his attention away. Snatching the camera up, he documents the Phoenix Lights—a set of mysterious luminescent formations in the sky above. Despite his best zoom efforts, the lights vanish just as quickly as they appeared, leaving him secretly disappointed. As the family speculates that the phenomenon might be military-related, Josh confidently suggests they’ve witnessed a UFO, to the disbelief of his family. Their skepticism intensifies as military jets thunder overhead, unsettling the festive atmosphere.

With the nostalgic footage wrapped, we hear a voice-over from an adult Sophie (Florence Hartigan), reflecting on the night as a lasting memory of her brother. The narrative soon reveals that Josh and two of his friends vanished shortly after that event, leaving no trace behind. Now, Sophie returns to Phoenix, intent on filming a documentary to uncover the mystery of her brother’s disappearance. Upon her arrival at the airport, she is greeted by her father, with whom she shares strained familial ties, a residual effect from the aftermath of Josh’s disappearance which prompted their parents’ divorce.

Sophie’s mission is twofold: to document her brother’s story and to aid in packing their childhood home, including Josh’s untouched room, a time capsule of his absence. As she browses through old belongings, she inquires about any remaining videotapes of Josh, which her mother supplies—a box brimming with their childhood memories. These tapes include newscasts that highlight the uncanny events following the Phoenix Lights, featuring interviews where both Josh and his father had garnered local fame for their footage. The news reports speculate wildly about the lights’ origins, with one notably featuring the then-Governor of Arizona mocking the possibility of extraterrestrial life.

The tapes reveal Josh venturing to create his own documentary concerning the lights alongside his schoolmate Ashley, also keen on journalism. Their initially awkward exchanges gradually blossom into genuine camaraderie, as we see him interviewing her and gaining insights for his project. The current footage of Ashley’s parents paints a picture of a charming girl hidden behind familial pressures, hinting at the tumult in her life, especially concerning her dream to chase journalism over law.

As their research unfolds, Josh and Ashley engage with astronomers who dismiss the notion of UFOs, suggesting the lights were likely military flares instead. Their next encounter is with a knowledgeable Native American elder, who despite not witnessing the lights, alludes to having encountered similar phenomena. In their quest for answers, they scour the library for historical accounts of unidentified aerial sightings, even finding biblical connections to wheels of fire that resonate with Josh’s experience. Their bond deepens over shared interests and light-hearted moments, like Ashley impersonating Contact’s lead character, showcasing their playful chemistry.

Chasing excitement, they decide to travel to a site mentioned by the elder, seeking further clarity amidst uncertainties. Their adventure however is punctuated by perplexing events; after spotting the lights during a newscast, they prepare to investigate, armed with curiosity. A sudden twist reveals police presence around the area where the lights were last reported, adding suspense as they record with anticipation. When possible sightings of the lights arise once again, the intrigue peaks leading into their road trip.

Fast forwarding, Sophie interviews local law enforcement involved in the search for her brother, where they express their bafflement over the lack of evidence following the mysterious disappearance. Frustration mounts as police uncover Mark’s car abandoned yet operational, with traces of his blood leading to more questions than answers. A pivotal find surfaces with the discovery of Josh’s camera holding the last recorded tape, revealing mundane moments turning ominous as they drive south, grappling with jealousy and intrigue regarding each other’s affections.

In the heart of their quest, oddities emerge, like the burnt remains of coyotes they stumble upon, accentuating the unsettling nature of their expedition. This leads Sophie back to the school in search of another camera, linking back to Ashley’s journalism class, but she hits a dead end with no records available.

As time ebbs away, Sophie continues to unravel layers of deception linked to the lights, ultimately confronting former officials regarding their silence on the matter. Despite her determined pursuit, answers remain elusive as she unwinds the mystery surrounding her brother’s fate.

Following a pivotal call about a box discovered in the school’s equipment storage, Sophie’s resolve strengthens, encountering the long-lost camera, intriguingly damaged yet holding another tape within. Eager to unveil the truth, Sophie watches the newly found footage, her expression shifts to shock, hinting at profound revelations as a series of new events unfold.

Through the newly played tape, viewers witness Josh, Ashley, and Mark wandering through the dark desert, as they become increasingly entranced by the unfolding mystery. They venture into a dramatic and tense atmosphere where their bonds are tested against the unfamiliar. As they navigate strange encounters fueled by excitement and fear, they soon find themselves amid terrifying phenomena, involving lights, disappearances, and the chilling realization that they might not return.

The narrative culminates in a unraveling of events that sweep them into a sinister force, leading to Josh’s frantic escape as he grapples with the daunting presence looming above. As the sky is filled with unsettling brightness and unearthly sounds, the camera glitches capture a harrowing climax, revealing the overwhelming mystery that ultimately consumes them. The film leaves viewers pondering the haunting enigma surrounding the Phoenix Lights, as text rolls across the screen, confirming that despite exhaustive searches, Josh, Ashley, and Mark vanished without a trace, a mystery forever etched into the fabric of their extraordinary story.