Season 1

Quicktime Crash-landing on a mountain side, THE VISITOR (formally Adam MacArthur) mysteriously emerges from the wreckage of the downed craft, seemingly unhurt. His sudden appearance creates a manhunt by opposing national security departments (including the FBI, headed by Douglas Wilcox, and the NSA, headed by Colonel James Vise), each with its own agenda to find out who Adam is, how he survived, and why he returned. It appears that Adam, missing in action since World War II, is still the young man he was 50 years ago prior to disappearing into the Bermuda Triangle. Adam eludes his pursuers by finding refuge with Nadine and Tyler Walden, a single mother and her 13-year-old son.

Adam MacArthur helps repressed and banished scientist Louis Farraday realize his life-long project to conquer gravity. Chased by both the FBI and Vise, they utilize this discovery to make their escape in a vintage World War II fighter plane

Adam MacArthur connects with his adult granddaughter while Vise and the FBI are hot on his trail.

Adam MacArthur is tormented by a message received from deep space. He and scientist Alex Burton try to decipher the message, but in a moment of synchronicity, both men are seriously injured and sent into a coma. They must try to navigate through their shared dream landscape and ultimately realize that the message may have dire consequences.

Adam joins a community of lost souls and discovers that they are waiting for an alien mothership to save them. Upon further investigation, he learns that the group's leader is developing a weapon that can cause mass destruction by ""canceling"" human brain wave activity. Adam must convince the young scientist working on the weapon to abandon the project before it's too late and turn his talents to aiding humanity.

To prevent a catastrophe, Adam urgently searches for mysterious objects that disappeared 30 years ago in a science lab accident. To find the objects, he befriends the Vietnam vet and his college sweetheart who survived the accident. As he tries to re-unite them, Adam finds himself in a race with time.

A radio DJ doing his annual ""War of the Worlds"" show on Halloween night witnesses the landing of an alien space craft, but no one believes him. Meanwhile, Adam knows the pilot of the unusual machine is looking for him and gets the help of two young siblings to help him avoid capture.

Things reach crisis point when Adam, his granddaughter Charlotte, Michael O'Ryan, and the FBI all converge to find Constance MacArthur, Adam's wife. While Adam is desperate to see his wife who he left in 1947, Michael O'Ryan will stop at nothing to prevent him from completing his mission on Earth and kidnaps Charlotte as bait. Meanwhile, the FBI closes in on Adam and Colonel Vise finally goes over the edge.

The FBI finally catches up to Adam and takes him to a federal prison for questioning. Meanwhile, Col. Vise experiences flashbacks of the experience that started his alien obsession. As they try to capture Adam, Michael O'Ryan discloses himself to Vise as his long lost friend.

After his escape from the FBI, Adam must get Michael O'Ryan and his craft back to their home or Earth will be endangered. Col. Vise has other plans, forcing Adam to go back to the FBI for help.

With the holidays approaching, Adam searches for a member of his family, but is delayed by a woman about to give birth. With the FBI and NSA hot on his trail, Adam helps the woman connect with her estranged scientist grandfather.

A frightened psychic woman forsees a terrible event that will affect humankind and Adam shows her how to use her special abilities to prevent the chain of events from unfolding. Meanwhile, Col. Vise is diagnosed with a bizarre illness.

Just when the FBI and NSA finally catch up to Adam, who is abducted by an alien spaceship right before their eyes. On board, Adam discovers that he was taken by a group of fellow abductees who put him on trial for his actions on Earth. Adam must defend why he disobeyed the ""Elders"" rules on non-intervention and justify his mission to the others.