Runt

Vic uses a drawing that Cal accidentally dropped into Gabriella's bag to convince the principal that Cal is stalking her. This ruse shifts suspicion away from Vic's own bullying and onto Cal, effectively clearing Vic while pinning the trouble on his rival. The manipulation works because the principal believes Cal's interest in Gabriella makes him a plausible suspect.

Earlier, Vic had threatened Cal in the hallway about his interest in Gabriella, showing his possessive attitude.

Cecily never reports Vic's assault because her father had just been paroled from prison, and she feared his reaction to any police involvement. Her fear of her father's potential violence keeps her silent despite what Vic did to her. This reveals the additional layer of fear Cal faces, Cecily's home life is also dangerous.

Cecily's reluctance to involve authorities hints at deeper family issues throughout her interactions with Cal.

Cal returns home to find Runt's body dumped in a bin behind his house, a crushing moment that deepens his sense of loss and anger. Vic later mocks Cal by mimicking Runt's whine and implying Cal killed the dog, which provokes Cal toward vengeance. Runt's death becomes the catalyst for Cal's most significant act of sabotage.

Runt is introduced as Cal's only true companion, making his loss devastating rather than incidental.

After Vic brutally beats Cal outside the party while Cecily escapes, Cal's rage boils over and he vandalizes Vic's prized car the next day. This act marks his transition from passive victim to someone willing to fight back. The car destruction signals the feud between Cal and Vic has escalated beyond verbal threats.

The attack at the party, especially on Cal, triggers this retaliatory act of vandalism.

After learning the football team uses performance-enhancing drugs and motivated by Runt's death and Vic's mockery, Cal sneaks into the locker room on game day and spikes their drugs with cleaning fluid. The cleaning fluid causes the team to suffer ill effects during the game, exposing the doping scandal. This act of sabotage is Cal's way of destroying Vic's team from within.

Ronny previously warned Cal about his father's drug-related death, foreshadowing the danger of substances in this environment.

When Borgie's father fires his pistol during the climactic fight, Cecily disarms the situation by taking the gun and handing Cal a baseball bat instead. Her intervention gives Cal a choice between lethal violence and restraint. Cecily acts as Cal's moral compass, urging him to walk away from killing Vic.

Cecily previously intervened in the school parking lot fight, taking the gun away and giving Cal a bat.

Cal chooses not to kill Vic despite having the opportunity, instead defeating him with the bat and walking away with Cecily. They head toward a homecoming party as police sirens echo in the background. This ending shows Cal rejecting murder but still committing brutal violence and facing an uncertain future with law enforcement approaching.

Cecily's earlier plea for Cal to walk away from the brink echoes in this final choice.

Cal's revenge stems from a accumulation of traumas: relentless bullying, being framed for stalking, the brutal attack at the party, Runt's death, and Vic's cruel mockery about the dog. Each provocation pushes Cal further from his goal of staying quiet and focusing on his UCLA scholarship. His vengeance represents both personal justice and emotional release in an environment that offers him no protection.

Cal's initial strategy is to stay quiet and focus on studies, showing how Vic's actions erode his patience.

Vic's football team uses performance-enhancing drugs to gain a competitive edge. Cal discovers this doping scheme and uses it as leverage for his sabotage. By contaminating their drugs with cleaning fluid on game day, Cal exposes the team's cheating and causes them to falter during the crucial match.

Ronny shares a cautionary tale about drugs, foreshadowing the doping subplot.

Ronny becomes one of Cal's first real friends, inviting him to bowling and the beach, helping Cal feel seen by peers who previously overlooked him. Ronny also shares a dark story about his father tainting drugs with cleaning fluid, which foreshadows Cal's own method of sabotage. Through Ronny, Cal experiences a broader social world beyond his isolation.

Ronny's drug warning directly influences how Cal chooses to sabotage Vic's team.