Jang Ga-Pil is an ordinary middle-aged father. One day, he returns home to learn that his teenage daughter was assaulted by a group of guys at a karaoke bar. He then concocts a plan to stab the boy on his way to school.

A salary man finds that his daughter has been assaulted by high school boys, including the school boxing star from an important government family, Tae-wook. Desperate to protect his daughter, he plans to stab Tae-wook on the way to school. He is stopped by a student, Seung-suk, who agrees to train him to fight so that he can face Tae-wook honorably. The movie is based on Kaneshiro Kazuki's novel "Fly, Daddy, Fly", which has a similar Japanese movie based on it as well.—Jones

An ordinary businessman in his forties, JANG Ga-pil returns home one day to find his daughter attacked by teenage hoodlums, including school boxing star KANG Tae-wook. Realizing that he has no background and money to fight back, he plans to stab KANG on the way to school. This fails miserably, but another student named GO Seung-suk agrees to teach Ga-pil to fight - in only 45 days.—Colleen16

A plain'ole, everyday salary man, Jang Ga Pil ([[Lee Moon Sik]]), discovers that his 17-year-old daughter, Jang Da Mi was sexually assaulted by a wealthy high school boxer. When he confronts, star boxer, Tae Wook's coach and advisor they threaten him and tell him that it was his daughter that brought it upon herself. So out of frustration and anger Ga Pil enters into the school lot of whick Tae Wook attends, carrying a knife hidden in a roll of newspaper. As school ended and students departed the school building Ga Pil nervously drops the knife for all to see. He points it around the gathered students out of fear, when a mysterious face shows up through the crowded students. In steady movement Go Seung Suk ([[Lee Joon Gi]]) walks right up to Ga Pil and severes him a blow to head that knocked him out. In an abandoned room near the school Ga Pil meets Go Seung Suk and his friends, Oh Se Jung and Chae Subin, where they brainstorm a plan for Ga Pil to gain his revenge and beat Tae Wook. For the seemingly impossible task he asks Go Seung Suk , a rebellious high school student with talent for fighting, to train him in only 45 days. So all three boys get together to train Ga Pil while at the same time kept records of his success through the training to show his daughter what kind of father Ga Pil is. When the training came to an end, the trio setup up a private show in the gymnasium where Seung Suk loured Tae Wook, thinking it was a match between himself and Go Seung Suk. As the gymnasium filled with students Ga Pil came out in boxing attire above a business suit prepared for the matched. The first round had Go Seung Suk fighting Tae Wook's friends, where they lost and the second round was with Tae Wook versus Ga Pil. The two hit it off in a fight, but which one will win the match?—Colleen16