On Halloween night, Oliver wears his old Batman costume and layers a Grim Reaper robe over it. Nathan wears his mother’s pink leggings and a black shirt beneath his own robe, dressing as Squidward from SpongeBob SquarePants. They hide the Big Wheel in bushes near the school and enter the packed gymnasium. Stinky arrives with “ME” written on his forehead and a frozen fish to demonstrate he does not actually stink.

Oliver and Nathan slip out and remove their robes. Oliver, in his Batman costume, successfully rides the Big Wheel down the hall while Nathan films. They upload the video to the seventh-grade chat under the alias “Freedom Avenger.” When Oliver insists that Nathan take a turn, Nathan crashes into the pedestal holding the 1974 state championship field hockey trophy, shattering it.

Panicking, they bundle the broken pieces in Oliver’s cape and attempt to bury them in the athletic field’s sandpit. High school boys ambush them, steal the bundle thinking it contains candy, and shove them into the muddy pit. The boys return to the dance covered in dirt, still carrying shovels. They accidentally win the Best Costume contest as gravediggers, receiving cartons of unsold Flaxplosion bars as their prize.

The morning after Halloween, Principal Candiotti holds an emergency assembly about the missing 1974 field hockey trophy. Nathan is consumed with guilt, while Oliver maintains perfect innocence. After the assembly, they spot the Big Wheel sitting in the lost-and-found box and suspect it is a trap to identify the thief.

In homeroom, Mr. Aidact confronts them with the Big Wheel video and produces a tiny gray thread he found on Oliver’s robe that matches his Batman costume. He identifies them as the pranksters but does not connect them to the missing trophy. Mr. Aidact sentences them to two more weeks of detention. Both boys are immensely relieved to have avoided suspicion for the trophy’s disappearance.

Weeks after Halloween, Principal Candiotti has offered a $100 reward for the missing trophy. Rosalie reflects on her disappointing experience with field hockey, noting that Mr. Aidact’s coaching is ineffective because it is purely theoretical. On the way to their first game, against Sheridan Middle School, the team bus breaks down. Mr. Perkins opens his briefcase, which contains tools, and quickly repairs the engine.

At the game, Rosalie’s mother is the only fan from Brightling. The team falls behind immediately, trailing five to zero by halftime. When Mr. Aidact offers no halftime speech, Rosalie tries to excuse the loss, but he insists the goal is to win.

Early in the second half, Sheridan scores again. Mr. Aidact disputes the call, and the umpire ejects him from the game. From the parking lot, Mr. Aidact climbs onto the team bus roof to continue watching. When the Sheridan players laugh at their coach, the Brightling team becomes furious and begins playing aggressively. Rosalie steals the ball and, following Mr. Aidact’s shouted command, passes to Cassidy for their first goal.

The team mounts a dramatic comeback. In the final seconds, Rosalie takes a shot that the goalie saves, but Cassidy scores on the rebound as time expires, tying the game six to six. Mr. Aidact leaps the fence and celebrates with the team, singing Queen’s “We Are the Champions.” Rosalie’s mother hugs the coach instead of her daughter.

Paul Perkins submits a confidential report to the Department of Education regarding Project: AIDACT. He notes that AIDACT’s ability to adapt to new situations exceeds expectations but warns of a downside: AIDACT absorbs and exaggerates the enthusiasm observed in others. Perkins cites a complaint from a field hockey umpire and expresses concern about AIDACT’s increasing tendency to sing and rap. The project status is listed as green. Special expenses include repairs to the dented roof of the school bus.

Stinky observes that detention has become crowded because Mr. Aidact now advises the school’s Trivia Club, which meets during detention. He realizes he inadvertently caused the club’s formation by spreading word of Mr. Aidact’s encyclopedic knowledge of song lyrics. After Stinky impresses the group with his knowledge of rap music, Mr. Aidact convinces him to join.

One morning before school, Stinky witnesses Darryl Yarmolenko being bullied by his father during basketball practice in the gym. When Mr. Aidact and Mr. Perkins arrive, Mr. Aidact intervenes, telling Mr. Yarmolenko he is putting too much pressure on his son. Mr. Yarmolenko mocks Mr. Aidact’s lack of basketball experience. After missing a few shots, Mr. Aidact begins sinking every basket, including from half court, explaining it as simply a physics problem.

A humiliated Mr. Yarmolenko leaves. Though Darryl takes his frustration out on Stinky by using his hated nickname, Stinky feels sympathy after witnessing the bullying and advises Darryl to get a detention so that he doesn’t have to go home.

In detention, Oliver tells Nathan that Mr. Aidact’s abilities are impossible, and he is determined to investigate. After school, they locate an address for Paul Perkins. The next morning, they stake out Perkins’s apartment and watch Mr. Aidact emerge; peeking through a window, they glimpse Perkins in a bedroom, revealing that they are roommates.

After school, Oliver retrieves his old toy periscope. He and Nathan return to the complex and spy through a window gap. Oliver watches Mr. Aidact unpack groceries, including three cans of WD-40, then stand motionless in the living room. Perkins opens his briefcase, revealing a full set of precision tools inside. Using a tiny wrench, Perkins opens panels on Mr. Aidact’s forearms, revealing wires, circuits, and chips instead of flesh and bone. He performs maintenance on multiple panels across Mr. Aidact’s body, applies WD-40, and connects a laptop to complete an upload. Stunned, Oliver and Nathan conclude that their teacher is not human.

At Nathan’s house, they go online to research further. They find a 2018 article from Educator’s Digest about a canceled Department of Education project called AIDACT, which stands for “Artificially Intelligent Designated Android Classroom Teacher.” The project aimed to place convincingly human robotic teachers in classrooms, each accompanied by a project engineer. The program was shelved because the AI technology was not advanced enough to meet diverse student needs.

Oliver and Nathan conclude that the project was restarted with improved technology, explaining Mr. Aidact’s superhuman abilities and confirming Perkins as his engineer. Oliver insists they keep their discovery secret, arguing that they can use the information as potential extortion material if they are ever connected to the missing trophy. He also notes that having a robot coach gives their field hockey team a significant advantage.

During another Brightling field hockey victory, Principal Candiotti reflects on the team’s success, their fifth win in a row, and accepts that the 1974 trophy is gone forever. Two teachers, Syesha Berg and Kelly Tapper, sit on the bleachers with her and complain about Mr. Aidact. Berg reports that students are obsessed with rapping and song lyrics because of Mr. Aidact’s influence, while Tapper notes that his Trivia Club is confusing students, who now mix pop culture with facts.

Candiotti explains that Mr. Aidact learns from students and reflects their interests back at them, and she points out that the faculty benefits from Mr. Aidact handling undesirable duties, like recess monitoring. On the field, Mr. Aidact loudly disputes an umpire’s call. When the call goes against him, he throws his hat with such force that it embeds in a tree trunk. Candiotti points out that Paul Perkins sends a real-time wireless command to calm Mr. Aidact down, but she explains that the AI treats such prompts only as suggestions.

The teachers express fear that robots will eventually replace them. After the Bobcats win, Candiotti watches Mr. Aidact celebrate and wonders if a robot could one day replace principals as well.