Hong Dae-young is a 37 year old divorced man, he loves his twin children, Hong Si-ah and Hong-Si-woo very much and knows everything about them... or, well at least he thought he did. One late night, he decided to visit his old high school, he got into the gym and decided to shoot a few hoops, but as he was throwing them, he made a wish. "I wish to be 18 again" Then he shot it and it landed in, suddenly a security guard (or something) came in yelling Security guard: "Hey kid! get out of here, school's closed!" Hong Dae-young quickly ran out, when he got out he was confused though Dae-young: "how could he mistake a 37 year old for a kid? Maybe it was the lighting... but either way, my frame is much bigger than a high schoolers."

The next day Hong Dae-young wakes up and gets ready, he spent the night at his friend Ko Deok-Jin's place since he doesn't have his own place. They've been friends for many years, but when Dae-young goes downstairs, he's met with Deok-jin screaming and chasing him around with a bat like he's an intruder, it wasn't until later that they both realize what happened. Dae-young explained the basketball wish thing to him. Just then, they got an idea to send him back to school with Ko Deok-Jin acting as Dae-youngs father, but he needed a new name since he went there 20 years ago, they decide his new name will be Go Woo-young. After Woo-young got registered into school, he started his first day of school on Monday. When he walked the halls, everyone would stare, he was extremely handsome, he didn't realize why everyone was staring, assuming it was because he was new. Halfway through third period, he went to use the bathroom, but he heard sniffling coming from a stall, he walked over and seen it locked from the outside so he opened it to reveal his son, Hong Si-woo Woo-young: "What the hell happened?" Si-woo: "Just leave it or you'll get bullied too" Si-woo left. Woo-young was left confused, wondering when this started and where Si-ah was through all of this, why no one came to him...