An alien security officer comes to Earth to track fugitives from his planetary system who have taken over the bodies of Earthmen. Unfortunately, while they enter human bodies and thus have a knowledge of humanity, the alien bases his physique on a poster of an underwear model for the Cole brand. Thus the alien (""Cole"") is pretty much clueless about humans and human physiology. A passing bar owner, Mel Porter, takes pity on him and takes him back to her hotel. ""Cole"" quickly cobbles together some Earth technology to track one of the escapees, Rhee, who killed his wife and child. He defeats Rhee thanks to his ""time-stop"" abilities and removes her essence from the human body she inhabits. He also meets Zin, a scientific genius and alien who masterminded the escape. At the end Mel takes on Cole full-time at her bar while Cole prepares to track more of the escapees.

Using his extrasensory powers, Cole figures out how Zin got his confederates into Chicago: by taking over the passengers on a train. Although Cole taps into the station's camera, he can't get a clear look at who they are. Meanwhile, an Inixian named Kaden is distributing an alien drug not only to his fellow criminals, but to humans as well. One of Jess' friends has a heart attack induced by the drug. Cole tracks the gas emissions caused by the drug production and follows Kaden to one of his traveling drug-clubs. Displaying a new ability to temporarily change his body, Cole duplicates one of the guards and manages to get close enough to Kaden to capture his life force.

Two brother/related Orsians, Raahm and Saahm, are trying to track down something from the Roswell crash site. Cole manages to capture Saahm, and uses his essence to intercept the mental transmissions from his ""brother"" with the aid of Earth-Jello. Following the messages, Cole tracks Raahm to Area 51 and tries to stop him from breaking into the military base and grabbing a crystal map. Raahm tells his brother to contact Zin so they can sell the map, but Cole intercepts the message. The two meet in the Roswell cafe, and after a confrontation meet out back to fight. Cole is vulnerable to cold, including a special spray can that Raahm has rigged up. However, Cole falls into a cloud of steam and revitalizes, and proves triumphant. However, Raahm no longer has the crystal map. Cole departs, unaware that the local waitress found it where Raahm hid it and it is now part of her Roswell ""alien"" collection of toys and gimcracks.

Cole is in the middle of pursuing Trof (an Enixian) and about to lose his life when a concealed alien, Nestov, comes to his aid. Cole captures Trof and then prepares to capture Nestov, who asks for his help. Nestov's host, Darian Fawley, was on the train returning with money from a kidnapping when Nestov and the others took over the people on the train. Now Nestov has the money but the rest of the kidnappers are after him because he gave the money to Zin. Cole agrees to help. The kidnapping is still underway, with the kidnappers holding the girl ransom for yet more money. Cole and Nestov track down the girl, only to discover that she had created the whole scheme along with Nestov's host body to get money from her rich father. Cole captures the girl and her accomplice, but lets Nestov go in appreciation of his help...and as a future resource in his attempts to capture the other prisoners.

An Enixian named Jax is knowingly spreading a dealy disease to women through seduction,his only outlet for a buildup of a toxic substance inside him,and Mel is getting personally involved.

A blind man is led into the middle of an intersection and left to be run over by his German Shephard. While picking up Mel from an aborted date, Cole senses the presence of one of his prisoners, and soon determines the German Shephard has been taken over by one of the last arrivals on the train: Medoran, Zin's bodyguard. Zin is putting his bodyguard to use, killing a councilwoman who stands in the way of his desire to have a district of Chicago rezoned. Cole tracks down the dog, which can shift forms into a werewolf-like humanoid, and manages to capture it.

Cole is pursuing an alien Nodulian, Kres, who is a ""courier""/smuggler. Kres is captured by U.S. government agents and taken into custody. Cole eludes them and uses satellite photography to locate the military base they've taken Kres to. Cole breaks in and discovers Kres is being tortured by Dr. Connelly, who knows that he is an alien. The government knows all about the energy burst that brought the escaped prisoners to Earth, and that Kres has deserted ""his"" human wife and family after being possessed. Kres is susceptible to heat, being an Nodulian. Cole is captured and subjected to the same treatment, which reenergizes him. Connelly realizes that and cools him down. Cole manages to escape using hypertime, but is captured with a fire extinguisher when Connelly lowers the base's air temperature. Kres has escaped from his cell and using an experimental hypertime simulator that Zin created, manages to free Cole. Cole has Mel download a virus into the base's computer, destroying all record

Zin hires the billboard actor whom Cole based his physical appearance on to participate in his plan to frame Cole for murder.

A young girl, Jamie Swenson, miraculously recovers from an illness and subsequently heals an electrocuted boy. This catches the attention of Cole, who investigates. Jamie has been taken over by Lontoria, a Cyrrhonian prisoner (of the same race as Cole). who escaped from Satrap. She was a political prisoner who thought Zin would give her a second chance on Earth, and she's been attempting to help humanity once she arrived. Zin (passing as a movie producer) wants her to use her powers for his own ends, and the local sheriff is another of the escaped prisoners. Cole is conflicted because he and Lontoria were friends. Meanwhile, the local priest, Father Creighton, believes that ""Jamie's"" powers are God-given, and tries to give her refuge in a church. Zin and the sheriff go after Jamie and Cole intervenes, defeating the sheriff but being fatally wounded by an energy gun Zin employs that was based on Lonotonio's weapon research. Zin is forced to flee and Lonotonio gives up almost all of her

The U.S. government project devoted to detecting aliens (from ""Breach"") is back in action. They are keeping the body of Wes Tarber, previously inhabited by the Nodulian Kres alive, and bring Zan (disguised as a ""Dr. Armstrong"") in to revive him. Zan succeeds by injecting it with the essence of Ramel, who didn't get a body in the original takeover because there weren't enough humans on the train. Zin needs access to files in the complex and revives Ramel to get in good, but kills the general he's bribing when the general gets antsy. Meanwhile Cole is analyzing Mel's grandmother's key, which apparently opens some kind of ""door"" beneath the Watchfire. Ramel attacks Cole, who killed his brother previously, but Cole escapes. Cole sneaks into the complex, and finds out that a Vardian ship piloted by an ""Arkin"" crashed into Lake Michigan. A ""Dr. Milos Sandborn"" interrogated the alien and then disappeared before giving his files to the government. Zin wants the files and needs Ramel to help se

Nestov warns Cole that Zin has created a gun that permanently nullifes Cirronian energies, turning them into normal humans for good. The two break into one of Zin's bases and steal it...only for Nestov to turn around and shoot Cole with it! He also takes Mel captive and ties them up, then invites Zin into the Watchfire and gives him her grandmother's key. They manage to get free and when Mel wields the Collector (which can only be triggered by Cirronian energies) she activates it! Cole finally figures out that Mel and her ancestors were part of a Mygar breeding program. She ""jump starts"" him back into his energized state, while Zin unearths the vault beneath the Watchfire and goes down into it. Mel and Cole defeat Zin's henchmen (with Mel using the Collector on one of them!). Nestov reveals he was actually planning a triple-cross, and was hoping Zin would leave. Unfortunately, Cole determines the Vardian device is a universal-destructor unit that Zin plans to use to gain absolute power

After bringing in another escapee after some tests, Cole determines a way to zap all of the remaining prisoners off Earth and back to Sartop at the same time by remote. However, one of the currently held lifeforces is contaminating the process, and he and Mel desperately try to determine which one before the wormhole closes. Things get complicated when Cole is zapped by an energy burst and loses his memory. He gets it back with some prodding from Mel, and they identify the ""contaminated"" lifeforce just in time and get rid of every remaining prisoner on Earth. Cole goes back, his mission completed. But then he returns, realizing his home is on Earth with Mel. But as they celebrate, we see the display screen show all the fugitive prisoners reappearing all over the U.S.