The investigators monitor the activity of the AUTEC (Atlantic Undersea Test and Evaluation Center), which is used by the U.S. Navy for underwater research, but the increasing reports of UFO and USO activity surrounding the facility have lead to rumors the base is testing alien technology.

The team looks into the claims of undercover investigators and former military personnel that an alien base exists somewhere below the New Mexico desert where human-alien hybrid experiments are being performed and how the beings there actually had a deadly conflict with human infiltrators.

For years, the team has been tracking an elusive prey only seen at night--ships, shaped like triangles, impossibly huge, and videotaped over cities around the world. But are they ours, or theirs? The team investigates numerous UFO sightings that have recently been reported in Sonora, California, a charming old West town nestled in the Sierra Nevada Mountain Range nicknamed Triangle Alley. What makes these sightings so compelling are rare daytime footage of triangles in flight. This footage will be digitally analyzed to determine if these are indeed UFOs and not military jets. The team will also visit Texas to speak to military experts and witnesses to compelling triangle sightings. It's speculated that these triangle craft have been visiting us for centuries

The team ventures to Germany and Poland to investigate rumors that the Third Reich had reverse engineered alien technology and may have produced a functional spacecraft, and how some of this technology was captured by the United States and helped jump start the U.S. space program.

The investigators analyze various UFO cases from around the world through the Freedom of Information Act, separating fact from fiction to determine what are obvious hoaxes and what could be legitimate evidence of UFO phenomena.

Continuing on the trail of the MIBs, the hunters follow the agent's supposed connections to a remote, military testing facility, the Dugway Proving Ground near Dugway, Utah. Dubbed by UFO watchers as "Area 52" and "the New Area 51" there have been numerous reports and video evidence of UFO activity surrounding the base for the past 10 years.

The team tries to gather insight on the military's "First Response" protocols, the alleged recovery and cover-up procedures that are followed in case of a UFO incident. The investigation takes them to a claim of a military pursuit of multiple UFOs near Long Beach, California and a return visit to the supposed UFO crash in Needles, California in 2008.

The hunters delve into cases involving witness interrogation by mysterious agents known as the "Men in Black" (MIBs), who sometimes appear suddenly after a UFO event, exhibit unusual behavior, know facts that have not been divulged by witnesses, and threaten the lives of those involved with severe consequences unless they remain silent about their encounter.

The team investigates the phenomena of cattle mutilations, investigating a recent slaughter and following patterns of other cases, as well as sightings of black helicopters which have led some to believe the military may be involved in the killings as part of a secret experiment.

The team studies two alleged alien abduction cases with alarmingly similar details that involve encounters with the creatures known as "Greys," and then they closely examine a strange humanoid skull found in Mexico that could be the remains of an alien-human hybrid.

The hunters delve into the mountain of reports from the Gulf Breeze, Florida UFO sighting wave of the early 1990s and then looks for possible connections to recent reports from Guantanamo Bay, Cuba of alleged Unidentified Submerged Objects (USOs) spotted rising from the ocean.

Investigating so-called "trace cases," the team studies supposed physical evidence left behind after various UFO sightings, from a strange glass-like rock found in Poland, to an odd piece of metal a Missouri man claims to have found after it was dropped from a UFO.

The team investigates the phenomena of orbs, (mysterious balls of light that appear to coincide with earthquakes), and travel to areas of orb activity in Arizona, Indiana and Missouri where some witnesses claim the spheres are intelligent and communicate through dreams and premonitions.