I expect every found footage movie I watch to suck, the genre long since played out. But little gems like Exists, The Banshee Chapter and now this one keep popping up.

The mysterious lights that appeared over the city of Phoenix, Arizona in 1997 are taken straight from true life. For the film, the video was taken from a suburban backyard by amateur documentarian Josh (Luke Spencer Roberts). The lights have interrupted the 6th birthday party being thrown by the family for Josh's six year old sister Sophie.

The framing device for the video footage is a documentary Sophie herself, now a young woman, is making about the sightings and subsequent events that led to her brother's disappearance along with two other local teens a few nights later.

She gets what remains of Josh's recording from her parents, and they contain the story of Josh asking two other kids to help him – Ashley (Chelsea Lopez), who he harbours a crush on, and Mark (Justin Matthews) because he has a car.

The trio talk to amateur astronomers with explanations of their own, a local Native American youth who tells stories of strange craft visiting Earth and communicating with his people, and go on the trail of other sightings in a nearby town late one night.

When they see a powerful spotlight emanating from a nearby mountaintop they climb up to see what looks like government officials in unmarked cars with no license plates setting up strange equipment that includes the powerful spotlight the kids have seen from across the desert.

Josh's tapes then chronicle his investigations into the path of the sightings and where he thinks they'll appear next. We learn that the only evidence Josh and his friends left behind the night they disappeared was their abandoned car on the side of the road and the camera with the tape Sophie's now watching left behind.

Hitting a dead end, Sophie just can't believe Josh didn't have another tape somewhere that's gone missing. When she's about to give up and get on a plane back home, she gets a call from the former school librarian, who reveals that the charred remains of an old VHS video camera have been discovered in a storage locker containing the school's old effects – since Josh was active in the AV club, it might be the tape Sophie's hoping for that reveals what happened.

The 25 year old camera is smashed and burned almost beyond recognition, but a local AV expert manages to extract and salvage the tape, and Sophie watches it to her horror. She goes to the local air force base to ask what they think about it, and her cameraman – left behind in their car – records what seems like a heated exchange between Sophie and the officer who comes to the guard gate to talk to her.

When she returns to the car and tells her partner the guy warned her not to let the footage come out, we're treated to the rest of Josh, Ashley and Mark's story.

The trio hike to the top of a nearby mountain the night of the lost footage. Once on top of the hill they witness a third unexplained event when a bright light appears in the distance, accelerates quickly and disperses into several distinct objects.

Elated at what they've seen, Josh, Mark and Ashley descend back down in the dark, but it's quickly clear they're lost and scared. When Mark climbs to the top of a nearby hill to see if he can spot the car, a loud rumble approaches and some huge, brightly lit object passes by just overhead. Terrified, Ashley and Josh ask Mark what happened when he reappears but he's irritated, not answering and simply insisting they get back.

Not long after, Mark gets violently sick, his nose bleeding, getting more disoriented, and eventually running off into the darkness, claiming to be able to hear someone calling to him.

Ashley and Josh begin to panic, Ashley soon exhibiting signs of the same sickness and with her hair falling out, but she suddenly leaps up, tells Josh she can her hear Dad calling to her from the desert and runs off after him. A petrified Josh gives chase and captures something incredible on film before Ashley and then he meet their fates.

There are certainly plot holes – who found the camera all those years ago and returned it to the school's possession, for instance? But the technical use of still and moving film stocks and footage gives the whole thing an air of authenticity. Josh's late 90s VHS footage is appropriately ghostly, the stills of forensic shots showing the abandoned car are very high quality with lots of contrast, and Sophie conducting her investigation are on modern digital.

The script by TS Nowlin and director Justin Barber gives you just enough glimpses of the amazing things Josh and his friend see to keep you interested, but maintain the realism of it being shot by three scared teenagers as they run and scream for their lives. None of what goes on is really explained and Sophie doesn't really get any closure even after you see what happened to her brother, but that only seems to add to the mystique.

There are some cool motifs like Native American petroglyphs and references to Ezekiel's Wheel from the Bible to give the moody scares a bit more context and the whole thing is well constructed, well acted, technically well directed, keeps you guessing, shows you the monster just enough, and proves there's plenty of life yet in what's long threatened to turn into a tired old genre.