"20th Century Boys: The Last Chapter" is a Japanese film that serves as the conclusion to the 20th Century Boys trilogy, based on the manga series by Naoki Urasawa. The story follows a group of childhood friends who must confront a mysterious cult led by a figure known as Friend, who threatens the world with a catastrophic plan. In this final installment, the protagonists work together to uncover the truth behind Friend's identity and intentions. As they navigate a web of deception and nostalgia, they strive to protect humanity from impending doom, culminating in a dramatic showdown that ties together the series' complex themes of friendship, betrayal, and hope.