Reports of a pizza-shaped UFO appearing in a field near Cardiff is all the evidence The Unexplainers need for yet another alien-hunting field trip.

When Wales' premiere paranormal investigators The Unexplainers head to the village of Pentyrch near Cardiff, Mike's hopes of visiting a favourite childhood destination are sabotaged by his colleague John's obsession with a recent UFO sighting. John thinks he's on to something when the village notice board starts talking to him in code, but as the duo start a building to building search for alien evidence, John's paranoia increases to intergalactic proportions.

Are the team being tracked by something worse than the Men in Black? Options for evidence run thin as The Unexplainers join some UFO hunters on a trek to the very location a UFO was spotted. But if a field full of sheep and a pizza slice the size of a football field aren't weird enough, things are about to get even more Unexplainable...