Yai Tua Rai Gub Nai Puan

Puan is a student who has just transferred from another province. On his very first day at school, he gets caught up in a fight between student gangs. In the middle of the chaos, Tonliw—the student prefect and president of the taekwondo club—appears and skillfully fights off the troublemakers, scattering them. Puan, however, stands frozen in shock. Tonliw mistakenly assumes that Puan is one of the delinquents, and this misunderstanding deepens when she sees him with the notorious “Three S Gang” (Sombat, Somchai, and Somnuek), a group of school bullies. In truth, Puan is being extorted by them, but Tonliw keeps a close eye on him, convinced he’s trouble.
Puan is actually gentle and peaceful, avoiding conflict whenever possible. He also takes care of his three mischievous younger siblings—Pan, Pun, and Parn—who see him as a hero. Because of this, Puan hides the bullying he suffers at school and pretends to be strong and capable in front of them.
One day, the Three S Gang plans a fight with students from another school. Tonliw finds out and locks the school gates to stop them, then reports them to the teachers. Furious at being punished, the gang plots revenge against her, but Arm—the student council president and Tonliw’s ideal man—steps in to help, making her admire him even more. Believing Puan is involved, Tonliw targets him instead and continues monitoring the gang closely.
Later, the school opens applications for more student prefects. The Three S Gang forces Puan to apply so he can act as their informant. Unable to refuse, Puan applies and endures Tonliw’s harsh tests before finally becoming a prefect. He is paired with Tonliw on patrol, secretly feeding information to the gang so they can avoid getting caught. Tonliw grows suspicious, while Puan feels increasingly guilty.
Over time, Puan helps Tonliw during their duties, and they grow closer. Tonliw meets his siblings and learns how they idolize him, though she initially believes they’re exaggerating his qualities. Feeling sympathy, she helps maintain Puan’s “hero” image in front of them. This makes Puan realize that Tonliw is actually kind and compassionate beneath her tough exterior.
As their bond deepens, complications arise with Tonliw’s best friend, Chokaew. Due to jealousy and manipulation by a trio of girls (Jeed, Nid, and Koi), Chokaew begins to believe Tonliw always takes good things away from her—including Arm, whom all the girls admire. Their friendship becomes strained, and Chokaew joins the trio in bullying and framing Tonliw.
Meanwhile, drugs begin spreading among students, prompting stricter school measures. Tonliw, who despises drugs, decides to run for student council president to promote anti-drug policies. The Three S Gang opposes her and conspires with Jeed to ruin her reputation by planting cigarettes in her bag. When teachers discover them, Tonliw is accused of misconduct. Jeed demands that she withdraw from the election.
To protect Tonliw, Puan falsely claims the cigarettes are his, leading her to misunderstand and distance herself from him. Arm also reveals that Puan has been acting as the gang’s informant, further breaking her trust. Heartbroken, Puan remains silent and accepts punishment, including two weeks of cleaning the gym.
Later, Tonliw learns from Puan’s siblings that he has asthma and cannot even be near cigarette smoke, realizing he took the blame for her. Touched, she helps him with his punishment, and they reconcile. Puan promises to stop being used by the gang.
At the same time, Tonliw and Chokaew mend their friendship, and Chokaew realizes Arm only sees her as a younger sister. Tonliw becomes confused about her feelings for Arm and Puan. Arm notices her growing affection for Puan but continues to follow his own heart.
On election day, Jeed cheats and wins the presidency. Though disappointed, Tonliw is encouraged by Puan, who reminds her she can still fight against drugs, with him and his siblings supporting her.
Meanwhile, the Three S Gang gets involved with a drug dealer named Hia Hao and begins selling drugs in school. Jeed discovers this but is blackmailed into silence. A young police officer, Athin, suspects drug activity at the school and investigates. Tonliw and the others volunteer to help.
Through their investigation, they discover the gang’s connection to Hia Hao. While gathering evidence, Tonliw is caught due to her impatience, leading to a confrontation. Puan bravely protects her and his siblings, getting injured in the process. Just as they are about to be harmed, Athin and the police arrive and arrest the criminals.
In the end, Tonliw realizes that Puan is not weak but truly brave and kind—the real hero her siblings always believed him to be, and her true ideal man. After everything is resolved, Tonliw and Puan continue their duties as fair and dedicated student prefects, maintaining order in their school together.