In the scorching summer of 1959, a young Taipei junior named Chang Chen, affectionately nicknamed Si'r, finds himself grappling with a significant setback after failing a vital exam. This failure deeply disappoints his ambitious father, who is acutely aware of the troubling delinquency engulfing night school students. As they listen to a radio broadcast that celebrates the achievements of successful students, it becomes clear that pivotal changes are on the horizon.
Fast forward to 1960, Si'r's insatiable curiosity compels him to join his close friend Cat on a secretive mission to observe an actress during a film shoot at a local studio. However, their stealthy antics do not go unnoticed, as a watchful guard catches them, leading to a comical yet hasty escape where they steal his flashlight to aid their getaway. Unbeknownst to them, this innocent escapade will inadvertently set off a chain of transformative events in their lives.
In a twist of fate, Si'r’s nighttime explorations lead him to a dimly lit classroom, where he inadvertently stumbles upon a passionate embrace between two lovers, their identities cloaked in anonymity. This unexpected encounter introduces him to the treacherous world of Little Park Boys and their rivals, the 217s. The Little Park Boys, helmed by the mysterious Honey, have been on the run from the police after a violent episode involving his girlfriend Ming, who has secrets of her own.
As Si'r becomes increasingly enmeshed in the rival gang dynamics, he finds himself at odds with Sly, the assertive leader of the Little Park Boys. Their rivalry intensifies after Si'r mistakenly assumes Sly and his girlfriend, Jade, are the couple he encountered earlier, inadvertently putting Sly in a precarious position. Amid this chaos, an unexpected friendship flourishes between Si'r and Ming, despite their starkly different life paths.
Efforts to forge peace are made when Sly devises a concert featuring artists from both gangs, aiming to foster camaraderie. However, Honey’s sudden return disrupts the proceedings, leading him to chastise Sly for his decisions, a confrontation that ironically elevates Sly’s status within the gang. As tensions smolder beneath the surface, Honey makes a controversial gesture by offering Si'r Ming’s hand in marriage, mistaking him for a stable figure in her life.
The night before the anticipated concert, Honey reappears outside the venue and instigates an altercation with the 217s and their leader, Shandong. Tragedy strikes when Shandong pushes Honey into oncoming traffic, leading to his untimely death. The Little Park Boys, infuriated by the police’s portrayal of the incident as an accident, decide to retaliate against the 217s amidst a furious typhoon. Armed with weapons provided by Ma, a wealthy classmate of Si'r, they execute a ruthless revenge that leaves the rival gang in utter chaos.
In the aftermath, Si'r's father becomes enmeshed in a perplexing controversy when he is apprehended and interrogated about past affiliations with the Chinese Communist Party. Although he is released, this encounter results in a career-damaging demotion that alters their lives forever. As Si'r and Ming's romance blossoms, Si'r attempts to excel academically, only to be provoked by Ming’s flirtations with other boys, including an older doctor. His fury culminates in an outburst that leads to his expulsion from school, spurring a determination to succeed in the transfer exams for a prestigious day school—an ambition met with Ming’s dismay, as she fears it will diminish their time together.
Meanwhile, Sly reemerges, seeking forgiveness for his past, only to drop a devastating revelation: Ming is now dating Ma, who happens to be Si'r's father. Overwhelmed by betrayal, Si'r turns to Jade, but his possessiveness and desire to control her lead to her withdrawal from their relationship. As the truth surfaces, Si'r realizes that the girl he saw kissing Sly was indeed Ming, not Jade—an agonizing realization that fills him with despair and resentment.
As tensions boil over, Si'r's emotional state spirals during a confrontation at Ma’s home, resulting in a reckless act where he steals Cat's knife. However, instead of facing his father, Si'r opts to confront Ming outside school, expressing anger over her perceived promiscuity. Ming responds with fierce admonition, asserting her independence and rejection of Si'r's attempts to reshape her identity.
In a harrowing climax, Si'r's outburst leads to a heartbreaking event that irreparably fractures their relationship. As the dust settles, he receives a fifteen-year prison sentence—a punishment exacerbated by extensive media attention surrounding the case.
Years later, as Si'r’s mother wanders through their now-empty home, she discovers her son's neglected school uniform—an evocative symbol of lost potential and the choices that have forever altered their lives. As the radio announces a list of exemplary students, the chilling weight of Si'r's decisions looms large, serving as a somber reminder of the profound consequences that arise from one's actions.
