"20th Century Boys" is a Japanese manga series created by Naoki Urasawa. It follows a group of childhood friends who reunite as adults to confront a mysterious cult led by a figure known as Friend. The story explores themes of friendship, nostalgia, and the impact of childhood dreams on adult life. The narrative spans several decades, intertwining the characters' past and present. As they uncover the cult's sinister plans, they must confront their own fears and the consequences of their actions. The series is known for its intricate plot and deep character development, making it a critically acclaimed work in the manga genre.