An animated pilot film for Ninja Bugei-chou released to the public over three decades later on Ninpuu Kamui Gaiden DVD volume 7. The pilot film was created in 1969 as director Nagisa Ooshima was wanting to make a TV animation to build off his controversial film from 1967. The pilot was rejected by Shirato himself (the original comic creator the film was based on) and the plan was changed to animate Ninpuu Kamui Gaiden instead, a side story to the Kamui Den manga also created by Shirato. Though with this change, Ooshima did not partake in Ninpuu Kamui Gaiden's production.

Based on the novel trilogy of the same name by MAYUMURA Taku (眉村 卓), Time Stranger is the story of a bunch of teenagers getting transported back in time through Japan's history, and getting mixed up with samurai shenanigans.

There exists the Cosmos Warriors, a team tasked with the duty of protecting freedom, justice, and peace of the universe. When the Master of the Cosmos Warriors was killed onboard a traveling spaceship and the rest of the passengers were kidnapped by the sinister Green People, Captain Leo soon uncovers a malicious plan that would put the fate of the people of Earth on the balance.

After coming across an advertisement about how anyone can lead an invasion force, young Don decides to establish a ragtag squad of his own to conquer the cosmos. Working alongside him are the aloof Pepu and the gaming-obsessed Chiku, though the value of their membership remains somewhat questionable. With his two henchmen by his side, the crew's inexperienced leader sets his sights on their first target: Earth. According to the manuals, Earth should be a simple enough target, but the situation spirals out of control right from the start. As it turns out, convincing over seven billion humans to simply roll over and accept their new overlord is no easy feat. Having been blown off by the entire human species, Don and his squadron touch down on Earth and begin their search for a way to subjugate humanity. However, with their unexpected failure, they face more pressing issues—namely, finding food and paying rent—so their plans for galactic domination will have to be put on hold for a little longer. [Written by MAL Rewrite]