Vortexes: The team travels to Sedona, Arizona, long known for strange phenomena, to interview witnesses to unexplained sightings of lights and objects in the skies. (S1, ep 9)

Underwater Area 51: The team investigate the highly secretive underwater testing facility AUTEC, said to be used by the US Navy for weapons testing and underwater research. (S3, ep 8)

Alien Fallout: After seeing an odd flying object in 1980, a woman was hospitalised as she lost clumps of hair and skin. The team reopens her potential 'alien effects' case. (S2, ep 8)

UFO Dogfights: The team examines a declassified US Department of Defense report which analyses an alleged encounter between a fighter pilot and a UFO. (S1, ep 8)

Alien Harvest: The team investigate eyewitness reports of cattle slaughter allegedly caused by UFOs, and are hot on the trail of a recent mutilation case. (S3, ep 7)

Lost UFO Files: The team recovers physicist James McDonald's lost research, including interviews with more than 500 witnesses of UFOs and revealing government documents. (S2, ep 7)

Invasion Texas 2008: The UFO Hunters travel to Stephenville, Texas to investigate multiple reports of strange lights in the sky. (S1, ep 7)

UFO Relic: The team examines the most compelling examples of UFO relics available, like a unique and other-worldly piece of metal in Missouri. (S3, ep 6)

Arizona Lights: On 13 March, 1997, a string of fiery globes were seen over Arizona, but earlier that night some eyewitnesses saw something more shocking . (S2, ep 6)

Crash and Retrieval: The team head to Mexico to the site of an alleged international incident involving the remains of a UFO wreck. (S1, ep 6)