The Substitute

Jonathan Shale survives a botched covert operation in Cuba that costs three of his platoon friends their lives. The mission's failure haunts him as he returns home to Miami and tries to put his past behind him.

Shale surprises his girlfriend, Jane Hetzko, at her apartment and she welcomes him with warmth. This homecoming sets the stage for his undercover assignment as a substitute teacher.

Jane Hetzko, a teacher at Columbus High, becomes a target of the Kings of Destruction after the attack that breaks her leg. The assault signals the gang's reach and the danger looming over Shale's loved one.

Shale infiltrates Columbus High as an Ivy League–educated, government-connected substitute. On his first day, he struggles to control the unruly class but uses his military discipline and combat techniques to gain the upper hand, while the principal warns him about corporal punishment.

Shale earns the students' respect by relating his war experiences to their gang-involved lives. He befriends fellow teacher Darrell Sherman and encounters Juan Lacas, a student who is also a local gang leader. This dynamic sets up tension within the school.

Shale installs surveillance cameras around the school and uncovers that Juan engineered the attack on Jane. He also learns that Juan is secretly colluding with Principal Rolle to distribute cocaine for a larger narcotics ring.

Shale and his mercenary team raid a drug deal at the school and seize cash from the operation. They use the money to buy music and sports equipment, claiming it is a donation to the school.

Sherman and a female student named Lisa witness drugs being loaded into a school bus while others are distracted. Sherman sacrifices himself by creating a distraction, allowing Shale to pursue the criminals and maintain the ruse.

One day, while Jerome runs the class, Lisa seeks Shale and he is unavailable. Jerome escorts Lisa to Jane's house, knowing Shale will return there, linking the school crisis to Jane's home.

Shale goes to Jane's apartment to rescue her but is overwhelmed by gang members. A neighbor's distraction allows him to break free and he methodically kills the gang, leaving Juan as the final threat who uses Jane as a human shield.

Jerome, tied up with Lisa, shoots Juan from behind, ending the standoff and freeing Jane. Lisa then explains to Shale what happened at the school with Mr. Sherman.

Shale and his four mercenary colleagues deploy to Columbus High School grounds to confront the remaining KOD members, Johnny Glades, a rival mercenary group led by Janus, and Rolle. They kill all the dealers and mercenaries, and only Shale and Joey Six survive, setting up their future as substitute teachers.