The third and final installment in the live-action "20th Century Boys" movie trilogy is set to premiere on August 29. It has now been announced that in order to keep the ending a secret, the final 10 minutes of the two-and-a-half-hour film will not be shown in any previews before the release date.

Approximately 40 advance screenings for the press are scheduled to start in late July, but all of them will screen a shortened version of the film without the last ten minutes. The ending is said to be different from the ending in the original manga, and will reveal the true nature of the "Friend" organization. The final scenes will also feature the introduction of key characters whose cast members have not yet been revealed.

In order to maintain as much secrecy as possible, two versions of the film's manuscript were prepared, one with the ending and one without. The complete script was given only to the actors appearing in the final scenes. One producer further stated that the scenes would be significantly modified after filming, reducing the number of people with knowledge of the full story to only about 10 people.