Plot

Yeon Shi-eun is a model student, who ranks at the top at his school. Physically, he appears like a weak boy, but, by using his smarts, tools, and psychology, he fights against violence that takes place inside and outside of his school.

Si Eun has no interest other than studying. When someone provokes him, he does not shy away from the fight that comes in his way. He has been smartly protecting himself by making quick decisions and made good use of his surroundings. However, he is in danger, and he gets help from Soo Ho and Bum Seok. A great friendship slowly emerges among the three of them while they try to survive in a school where bullying always happens. The ways Si Eun, Soo Ho, and Bum Seok deal with people and violence show how the feeble teenagers become strong.—Rakuten Viki

The drama depicts the story of a model student with the top 1% of grades who seems weak, Yeon Si-eun (Park Ji-hoon), who suddenly becomes 'prey' to a delinquent Jeon Yeong-bin (Lee Soo-gyeom) and gets embroiled in an incident. He decides not to back down and confront it with the help of another outsider, Ahn Soo-ho (Choi Hyun-wook), and a transfer student, Oh Beom-seok (Hong Kyung).

Weak Hero Class 1 (Hanja: Yakanyeongung Class 1) is a South Korean web series based on Naver webtoon Weak Hero by writer Seopass and illustrated by Kim Jin-seok (Razen), which was published in 2018. It stars Park Ji-hoon, Choi Hyun-wook, and Hong Kyung, directed and written by Yoo Soo-min and Han Jun-hee as the creative director. It is a strong action coming-of-age drama about a weak-looking boy, who fights against numerous violence with his friends.

The webtoon This is based on is described as such: "Once the bullies target you, it's game over. The school is run by tyrants whose favorite hobby is tormenting the weakest kids in class. But then Gray (Yeon SiEun) arrived. This mysterious new student threatens to dismantle the established order. He may be small in stature, but his calculative and brutal fighting leaves unsuspecting opponents lying on the floor begging for mercy. Now the school's toughest bullies have to scramble to take down this new and unusual hero."—WEBTOON