A Man's Man summary: Hansung is a thriving electronics company that was built on a work culture that is toxic, and Yuhyeon is announced to be its youngest CEO. Unfortunately, there is no one around to celebrate with him. After spending the night drinking and pondering about the past, he wakes up the following morning, 20 years younger, and at the start of his career. Through the knowledge and understanding he acquired as CEO, Yuhyeon resumes mending broken relationships and confronts the enablers of Hansung's ruthless working conditions. However, he is still unaware of the consequences that modifying the past may bring to his future.