Omar is an ex-con looking to rebuild a boxing career at the age of 35. He’s not having much luck.

Cade approaches him after the fight. Healy doesn’t want to associate with a wanted man, but Cade needs his help.

As our hero reveals, he's investigating the Atlanta Institute for Advanced Studies, which is recruiting fighters for a medical study. He tells Healy that the people behind the study murdered of his wife.

As he scrolls through the articles, Eddie asks Cade if Healy can be trusted. Cade is optimistic – Healy was disqualified from the Olympics when he took medication for a migraine, and has had hard times since, but he’s serious about putting his life back together.

Healy finishes looking at the site, and they tell him that they have traced funding of the Institute through shell companies to the Gua. Healy thinks they are crazy.

Healy and Cade go to the Institute, where they meat Dr. Mira Rubin. She takes a sample and prepares a room for them.

Rubin also shows them the fight room, where two boxers are expressing their manly feelings. She tells Healy and Cade that her research team is mapping the human genome, searching for the gene that controls aggression.

Healy is skeptical, commenting that he believes aggression from the environment. He means life, but she brings an important plot point in by showing him the lab’s temperature controls.

The doctors do a preliminary analysis of Healy’s blood. Galloway thinks Healy’s DNA could balance their current sequence, but he’ll need more samples.

"Our new fighter could be the answer," he says.

Healy gets a fight. As they watch him, Dr. Rubin introduces Cade to Dr. Galloway.

Galloway thinks he’s seen Cade before. Cade claims he just has one of those faces.

Healy trounces the other fighter, and doesn’t let up even when the doctors raise the temperature in the room. Galloway likes what he sees.

As Galloway and Rubin watch Healy, Cade slips out of the room and follows another doctor down a flight of stairs. She enters the secured "McGruder Wing."

That night, Cade tells Healy he’s seen what he needs to see, and is ready to sneak out. Healy refuses to go, saying that he doesn’t believe in aliens and that he can take care of himself.

 Eddie gets adventurous

Cade shrugs and goes to meet Eddie, who has located blueprints and a route into the McGruder Wing. He’s also done some research on the two doctors – Rubin has normal records and is probably human, while Galloway doesn’t seem to exist and is almost certainly a Gua.

Seemingly tired of sitting around in the trailer every episode, Eddie insists on helping infiltrate the facility. He justifies this by pointing out that Cade failed eighth grade science.

They slip into the wing, peering through a ventilation duct at Galloway’s lab. They listen as Galloway details the improvements he expects from the new warrior husk, and watch as he fires up the system for another experiment.

A perfect husk is pulled out of the machine. It’s alive!

 Nobody ever looks under the bed

Amazingly enough, Healy refuses to believe in supercharged alien warrior clones. As Eddie and Cade try to convince him, two security guards drop by looking for intruders, and Eddie is forced to hide under Cade’s bed.

Cade decides to gamble on Dr. Rubin’s humanity. Claiming he’s an investigator from the Department of Defense, he asks her to call the authorities and investigate the McGruder wing.

She calls security instead. He flees, telling her to "be careful."

Returning to the others, he outlines a plan – Cade will start a distraction and then try to kill the warrior prototype while they flee. Healy still refuses to go, but Cade makes him leave at gunpoint.

Dr. Rubin goes down to the McGruder Wing. She surprises Galloway, who tells him he can explain what he’s doing there.

She grabs his head and breaks his neck. She’s a Gua overseer secretly observing the experiment, and she is not happy that Galloway has exposed the operation.

Rae, the remaining researcher, tells Rubin that trainer "Jack Monroe" is the nefarious Cade Foster. Galloway did recognize him.

 Nobody ever looks in the ventilation shaft either

Cade makes Eddie hide in the ventilation system. Moments later, a security guard spots them and tries to stop them.

Healy tries to punch the guard out, and has a close encounter with Gua strength and speed. As they struggle, Healy impales the guard’s head on a coat rack, and is shocked to see him dissolve.

Moments later, Cade and Healy are surrounded by guards. Dr. Rubin is leading them.

"I understand you’re the best humanity has to offer," she tells Cade. "Get ready to face off against the best we have to offer."

 In touch with his sensitive side

Healy is completely freaked out by the existence of the aliens. He comforts himself with the belief that "everyone’s got a weak spot."

Cade tells Healy about the drug-like effect of salt on the Gua. As it happens, Healy keeps a jar of salt tablets in his kit bag.

They argue over who should go into the ring with the warrior prototype. Healy wins by knocking Cade unconscious.

Dr. Rubin comes in and congratulates Healy – he gets to be the first to fight the X-15. They take him to the lab for the fight.

Meanwhile, the doctor transfers her consciousness into the X-15. "It’s perfect", he/she says.

Cade recovers consciousness. Holding a handkerchief to his bleeding lip, he crushes salt tablets into powder

Eddie hails him from the ventilation duct. He’s lost Cade’s gun, but Cade tells him to go to the control room in the lab.

Healy prepares for the fight. The X-15 arrives, and the fight begins.

Cade picks the lock on his door, attracting the attention of the Gua guard. Seeing the ventilation shaft – which is only slightly bigger than a man’s head – the Gua demonstrates superior alien intelligence and peers into it without searching the rest of the room first.

Cade traps his head in the vent and breaks his neck.

 Never fight a man named after a jet

Healy tries to punch the X-15. The warrior grins and catches punch after punch in his meaty hands.

Tiring of this game, The X-15 knocks Healy down with one punch. Healy gets back up.

Eddie gets in the completely empty control room. He watches the X-15 beat the stuffing out of Healy.

Cade runs for the lab. The X-15 knocks Healy down again, but the doughty human fighter refuses to quit.

Cade arrives in the ring. He throws salt at the X-15, and it has no effect.

The X-15 explains that this new warrior prototype isn’t affected by salt.

"Everyone has a weakness," Cade insists.

"Not me," says the X-15. He grabs Cade’s throat.

Healy picks himself off the floor and launches another attack. The X-15 whirls and lands a brutal punch on Healy’s larynx.

It’s always the gloating that brings you down

He gloats over Healy, pointing out that he has Healy’s DNA. "I’ve beaten you with your own strength," he announces.

That gives Cade an idea. "Cold!" he shouts, "Eddie! Make it cold!"

Eddie searches for the lab’s temperature controls. Meanwhile, the X-15 decides to kill Cade with a leisurely strangling.

"Crazy" Eddie cranks up the air conditioning, triggering Healy’s tendency for migraines in the X-15. The X-15 goes looking for Excedrin.

Not finding it, he pulls a long, sharp piece of metal out of the wall, disabling the cooling system. He advances menacingly on Cade – who grabs the fallen piece of metal and stabs the X-15 through the heart with it.

The X-15 dies and dissolves.

Healy is dying. "You got him," Cade tells him, "You made the big time."

 Cleaning up after Cade Foster

The Gua dismantle the experiment. It will take years to replicate Galloway’s brilliant research.

However, the experiment wasn’t a total loss. Thanks to the handkerchief Cade used to mop the blood off his lip, they now have the DNA of Subject 117.