A 27-year-old washout gets turned into a high school kid for one year, and instead of using it to fix his life, he just becomes a better person by accident. The show knows the premise is borrowed, so it doesn't pretend, it builds everything around watching someone who has already failed learn that failure isn't permanent, just something you carry into the next room. By the final episodes you realize the real experiment wasn't about the drug at all, it was about whether someone could forgive themselves, and that's when it stops being a gimmick and becomes something you feel in your chest.
Kaizaki Arata is stuck. At twenty-seven, he's unemployed, rejected by every company that interviews him, and watching his life spiral with no clear path forward. Then a mysterious stranger offers him an impossible deal: take an experimental drug that'll rewind his body to seventeen, enroll back in high school, and become part of a secret research study for one year. The catch is simple but brutal. He can't tell anyone the truth, and when the year ends, everything goes back. What unfolds is part comedy, part reckoning. Kaizaki returns to a world of youth he thought he'd left behind, surrounded by real teenagers with real problems. He reconnects with genuine friendships, unexpected romance, and the messy complications of student life. But beneath the slice-of-life humor sits something heavier: a man watching his second chance slip away, forced to reckon with the choices that brought him here. Time loops differently when you know exactly how much of it you have left.