Set in a Chicago neighborhood nearly a decade after an occupation by an extra-terrestrial force, Captive State explores the lives on both sides of the conflict – the collaborators and dissidents.
A race of aliens invade Earth and seize control. Some humans become collaborators, while a rebel group called Phoenix is leading a secret revolution against the aliens (AKA Legislators).
Officer William Mulligan seeks out Phoenix and attempts to get help from Gabriel Drummond, son of Mulligan’s former partner. Gabriel’s brother Rafe is among the members of Phoenix who stage a bombing at a football stadium where a rally for the Legislators is held by planting the bomb on the mayor’s deputy to go off when he gets close to the Legislators. They see it as an attack and plan to destroy a major Chicago neighborhood unless the attackers are caught. Mulligan forces Gabriel to infiltrate Phoenix to save Rafe, who has been taken prisoner.
Gabriel finds a prostitute that has been leading Phoenix, and Mulligan’s men shoot her and find information on all Phoenix members. Some are caught while others kill themselves to avoid capture. Mulligan then gives Gabriel a video file showing his parents, plus the prostitute (Priscilla) and Mulligan, revealing that they were all part of Phoenix from the beginning, and the plan all along was for Mulligan to gain the aliens’ trust so that he can get into their Closed Zone and take them down from the inside.
An alien race has descended upon the planet. Authorities and armed forces are advised to stand by before making moves. A family of four is trying to drive to school, but the father cuts out of the line to get out of traffic. He takes the family down a restricted street and is shot at by cops. They make their way through a bridge before realizing something dangerous is at the other end. As the father tries to turn the car around, a creature emits a blast that vaporizes the mother and father. The two boys in the back are left holding each other in terror as one of the aliens comes toward the car to reveal its faceless appearance.
Over the next nine years, the aliens take control of the planet and are referred to as the Legislators. Several humans have sided with the Legislators and are helping them exploit the planet’s natural resources. The rich have benefited more from their alliance and the poor have suffered more for it. Humans are forced to carry implants in their necks that can be tracked. A secret insurgency group called Phoenix has been making attempts to strike the aliens’ Closed Zone, with the intent to wage an all-out war. The result of their first attack causes the Legislators to destroy Wicker Park
Chicago – A government official named William Mulligan (John Goodman) is spying on Gabriel Drummond (Ashton Sanders), who lives with his girlfriend Rula (Madeleine Brewer). He leaves to go to work with his friend Jurgis (Coulson Baker). Gabriel’s brother Rafe (Jonathan Majors) has a reputation among the people in the area prior to his apparent death.
Mulligan follows an address to a prostitute known only as Jane Doe (Vera Farmiga). She gives him a box giving him a lead on Phoenix. As he gathers evidence and discusses with his partner Kermode (Kevin J O’Connor), a professor named Charles Rittenhouse discusses with his cohort Patrick Ellison (James Ransone) that they are planning on making a break into the Closed Zone over Soldier Field that night, which will be the site of a rally that hopes to attract the Legislators.
Gabriel goes to his job at a factory where he downloads some information from a computer. He witnesses a coworker steal a powdered substance. He later meets with a young woman named Carrie (KiKi Layne), who rolls him a cigarette that he needs for a job. Later, the woman from earlier is being escorted by two masked men while she pleads fearfully for mercy. Gabriel then meets with Jurgis and shows hesitation about acting for this job, since he wants to go straight for Rula. They hear a siren outside, and the two run, but Gabriel is found by Mulligan. He questions him about Phoenix and Rafe, even mentioning that Gabriel’s father was his partner, but he refuses to talk to Mulligan.
Gabriel goes to a location he was given for the job to deliver the cigarette, but he is forcibly taken into a van. He is brought to meet Rafe, who is actually alive and leading Phoenix. Gabriel is overwhelmed and learns that Rafe was the only one in his group to survive an assault against the aliens, whom the group refers to as roaches. Rafe gives Gabriel money, but he wants his brother to come back with him and get their lives back to normal. Rafe is more concerned with launching an attack against the Legislators. Gabriel leaves, and Rafe opens the cigarette to find a coded message, which he passes on through a carrier pigeon.
Gabriel returns home to try and get Rula to leave with him, while Mulligan tracks and overhears his conversation. He hears Gabriel mention Rafe being alive and that Phoenix is planning something. He fails to convince Rula to go with him, so he runs off on his own. Mulligan pursu
es Gabriel, who quickly realizes he’s being followed and starts to run. Gabriel finds a hiding spot that turns out to be in the Closed Zone. He finds large tentacles that try to get him, but he hides in a booth and uses a special collar to keep the tracker off.
The members of Phoenix begin to set their plan in motion. Ellison delivers the code to his colleagues and is then assigned to target Robert Watts (Michael Collins), the mayor’s deputy who can get them close to the Legislators. The others are called together and undergo procedures to have their implants removed, although the surgery proves fatal for some. A clear sac-like material is then distributed to be used as a bomb that will be passed on by Watts.
Thousands of people gather at Soldier Field for the rally. Phoenix moves quickly to get by undetected as their plan is being carried out. Rafe manages to plant the bomb onto Watts just as the alien ship hovers over the stadium. As Watts approaches the Legislators in the halls of the stadium, the bomb detonates. Everyone starts to evacuate. Phoenix members run and are shot at but attempt to flee anyway. Rafe tries to run but is found by an alien similar to what killed his parents. It attacks Rafe, but one other Phoenix member manages to weaken the alien and help Rafe escape. They proceed to hide any evidence of their involvement, while Gabriel awakens and runs away with nowhere to go.
In the aftermath of the bombing, Mulligan meets with Commissioner Eugene Igoe (Kevin Dunn) over trying to stop Phoenix. Igoe wants to keep things smoothed over with the Legislators in the hopes that they can make their way off the planet due to its rapid decay. He then enters a pod that transports him into the Closed Zone.
As fireballs start shooting across the sky as a perceived retaliation by the Legislators, Mulligan leads a raid against Gabriel’s building to look for the brothers until Gabriel makes himself known and goes with Mulligan. He gets in touch with a Phoenix member and appears to threaten his family to get information on the others’ whereabouts. A bus carrying several members is stopped in a blacked out station garage before armed guards and an alien in a large suit enters the bus. It goes for one male Phoenix member, but he commits suicide before he can be captured. It then goes after Rafe, who fights back and gets off the bus but is taken down by Mulligan.
Gabriel is interrogated by Mulligan and is forcibly persuaded when he sees that Mulligan is keeping Rafe as a prisoner. Rafe pleads with Gabriel to not follow Mulligan, but it doesn’t look like he has a choice as Mulligan tells Gabriel that the Legislators want to level Pilsen the same way they did Wicker Park. Mulligan tasks Gabriel with infiltrating Phoenix’s cell by delivering a message. Gabriel makes it to their base and is recognized by Rittenhouse as one of his students. He escorts Gabriel to the apartment of Jane Doe. As she greets him, Mulligan orders his men to barge in and shoot her. Mulligan and Kermode later arrive to search the place and come across a wire behind the walls that leads to a space with hidden information and files.
Mulligan sits to meet with the Legislators to give them all the details on Phoenix. He convinces them that their network is neutralized, and he discloses that the prostitute’s real name was Priscilla Scott, as well as Igoe apparently being in on it when the recordings from her room are played. The Phoenix members are then outed, and some commit suicide to avoid being found. Mulligan is then instructed to go to the Closed Zone for further orders. The remaining Phoenix members are made to get into a Legislator ship which flies into the sky.
Mulligan later finds Gabriel and tells him Rafe is alive, but he doesn’t care since Rafe didn’t care about him either and his plan failed anyway. Mulligan says it may have been intentional for them to fail. He hands Gabriel a chip with something he must watch. Gabriel takes it to his job and plays it on a computer. It features what seems to be a baby shower for Gabriel’s mother. Priscilla and Rittenhouse are among the guests, which also includes none other than Mulligan himself, which means that he was part of Phoenix from the very beginning as part of a plan to gain the Legislators’ trust and infiltrate the Closed Zone. Gabriel finishes the video and deletes the footage. Mulligan is then seen being strapped and sent into the Closed Zone.
The credits show reports of Closed Zones being taken down across the country.