On Tanarak Island in Alaska, Dr. Jessica Shaw is driving down the road in her SUV when the sheriff and several thugs pull her over.
Det. Shaw brings Rita, Jessica's mother, to see Winston. She plays a message from Jessica explaining that she didn't think she'd be able to escape the island.
The sheriff pulls Jessica over and accuses her of speeding. She claims she has a medical emergency but he looks in the back and finds the body of a dead mining foreman, Hank Benson. She claims that she was taking the body for an autopsy, but the sheriff warns that the company won't like that.
Rita explains that Jessica has traveled across the world helping people. Winston warns that they've never operated in that part of the world, but Rita insists they can help and she doesn't believe that Jessica is lost like the Agrius Corporation claims.
Jessica drives away from the men, including their leader, Duke. She swerves to avoid an oncoming car and her SUV goes off the road and down a steep hill. Duke orders his men to go down there and recover her and Benson's corpse.
Winston goes over the file on Agrius with Chance. They've announced that they're restricting access to the island, supposedly for blasting, but Chance figures that it's a cover so they can seal off the island. Winston has investigated Benson's death and it appears that he died of a heart attack. They review a map of the island and figure Chance will need an official cover. Winston is skeptical that Guerrero can do it. Guerrero comes up with a cover ID for Chance as Paul Woodruff, a member of the Alaskan Bureau of Land and Mine Development. Chance departs while Winston works the corporate angle.
Chance goes in driving a Camaro and playing rock music. He arrives at the bridge going to the island and discovers that the sheriff and the Agrius thugs have closed off the island. When Chance shows his ID, the sheriff calls in and gets permission from Duke to let him in. However, they assign one of the Agrius thugs, Big Mike, to take him in by truck.
As they proceed in, Big Mike spots a smoke column in the woods and calls it in. Chance knocks the man out and takes his shotgun, and then goes to investigate. He finds the empty campsite and checks it out. Jessica tries to attack him with a syringe filled with morphine and he easily immobilizes her and explains why he's there. She assumes that he's a mercenary and Chance doesn't correct her, and they head back for the truck. As they go, Jessica explains was suffering from labored breathing and a rash, but he died from a pulmonary embolism. When she scheduled an autopsy on the mainland, Agrius sent men in and closed off the island. Jessica refused to walk away, figuring she owed Benson's family. Agrius pressured her and she realized something was going on.
Duke and his people find the unconscious Big Mike and orders his men to start searching the forest.
Guerrero slips in to Agrius pretending to be an employee and accesses their computer. He tracks two calls from Tanarak, to CEO Jason Banneker and Dr. David Patel, the head of research and development. Guerrero tells Winston he'll take care of Patel and slips away.
Chance plans to drive to the marina and steal a boat, and then get to the mainland. However, Duke and his man spot them and open fire. Chance returns fire to cover their escape but they find themselves at the edge of a cliff. They have no choice but to jump into the river below, despite Jessica's reluctance.
The couple escapes down river and Chance starts a fire while Jessica strips and removes her wet clothing to avoid hypothermia. They are still several miles away from the marina. Chance suggests they share body heat and they both insist that it's practical.
Winston meets with Guerrero, who reveals that he's abducted Dr. Patel when the scientist proved reluctant to talk.
Jessica explains that she felt she couldn't make a difference in common practice, and started traveling the world and visiting hot spots. She admits that she swore to help people that needed help, and figures that Chance wouldn't understand because she thinks he's a mercenary.
Winston and Guerrero take Patel back to the apartment and interrogate him. Guerrero checks his phone while Winston demands answers. When Patel proves reluctant, Guerrero offers to persuade him and Patel tells them that Agrius developed a dangerous chemical named propalyde.
Chance knocks out one of the thugs and takes his car, and then uses On Star to access a satellite and call Winston. They bring each other up to date, and Winston explains that Agrius is trying to cover up the use of an industrial solvent, propalyde, and that it's dangerous. They're covering up Benson's death to avoid a million-dollar lawsuit, and Agrius needs to eliminate Jessica. Winston and Chance conclude they need soil samples from the mind to get the evidence they need against Atrius. Chance warns that it won't end for the doctor even if she escapes the island. He suggests they get the proof they need and Jessica ends to stop the human suffering. Chance has Winston get a plane to a nearby airfield.
At the mining site, the fugitives check Benson's work logs and discover the shaft where he was working when he was contaminated.
Patel admits that Banneker cleared out all of the evidence of propalyde and there's no documentation. Guerrero finds an unidentified number in Patel's phone log and he explains that it's for Jon Taggart. Taggart is an evidence scrubber who works for corporations, and Guerrero knows about the man. Patel was sworn to secrecy. He figures Taggart has the evidence they need.
Chance and Jessica go to the shaft and look for propalyde. They find fresh wood used to close up a tunnel. While they explore, Duke discovers that they've come to the mines looking for proof. It's pre-rigged for demolitions and Duke tells his men to secure the entrance.
The fugitives find the propalyde barrels and collect the necessary samples. As they leave, an alarm goes off and Chance realizes it's a pre-blast warning. He gets Jessica back to safety just as an explosion collapses the entrance. The debris traps them, and Chance takes s shard of rock in the shoulder. As Jessica removes it, she explains that when she worked in Chicago, she let the administration pressure her to choose a cheaper treatment for a patient. Since then, she swore she'd never walk away from someone she was protecting, no matter the cost. Chance notes that he's been there, too. Once she removes the shard, they hear a hissing noise and discover that a carbon monoxide venting pipe was damaged in the leak, and filling the mine shaft with toxic gas.
Patel arranges to meet with Tarrant. When the fixer arrives, Guerrero gets in the car with him and explains that it's in his best interest to turn over the evidence he squirreled away to ensure that Agrius paid him. If he doesn't, Guerrero will go after Taggart's family.
Chance piles up tanks of acetylene and uses it to open up an adjoining shaft that leads to the surface. Duke hears the explosion and anticipates what Chance is up to, and goes to investigate. Meanwhile, Chance grabs Jessica and leaps off a shaft into a truck filled with dirt. As they get in, Duke's men arrive by truck and open fire. Chance drives off and has Jessica take the wheel while he returns fire. Several shots hit the truck's gas tanks. Duke and his men try to board. Chance knocks one off and struggles with Duke. He stuns the man long enough to grab a flare gun, pull Jessica off with him, and leap clear. As Duke prepares to shoot at them, Chance fires the flare gun and ignites the gas tanks, blowing up the truck and Duke with it. The fugitives look up as the plane arrives to take them to safety.
Banneker gets into his limo and finds Winston waiting for him. Winston has the evidence incriminating Agrius for use of propalyde and explains that it will all come out at the trial. He informs the CEO that the company will go down and Banneker will be in a minimum security prison. However, if Winston lets the authorities know that he tried to have Jessica killed, he'll serve hard time for conspiracy to commit murder. Winston agrees not to go public with the murder charge as long as Banneker makes sure no one touches Jessica, and that the CEO pays Winston everything in his checking account. Banneker considers for a few seconds and then takes out his checkbook.
Chance is playing with his dog Carmine when Jessica arrives. He realizes she's ready to go on another trip to Dakar to help those less fortunate. She invites him to look her up if she's ever there and he suggests a restaurant to her. As Jessica goes, Chance gives her Banneker's check to cover her expenses and let her keep up her good work.