Lee Ji-eun has had a crush on Jungkook since their first year of high school, little did she know that he felt the same way. But with a crazy girlfriend, a friend whose love goes unwanted and an overprotective brokenhearted brother they go through many obstacles. But one thing Jungkook keeps reminding Ji-eun is he'll spend 10,000 Hours or the rest of his life showing how much he loves her.