Bundled with the tenth limited-edition volume of Blood Lad manga.

When Gintoki apprehends a movie pirate at a premiere, he checks the camera's footage and finds himself transported to a bleak, post-apocalyptic version of Edo, where a mysterious epidemic called the "White Plague" has ravished the world's population. It turns out that the movie pirate wasn't a pirate after all—it was an android time machine, and Gintoki has been hurtled five years into the future! Shinpachi and Kagura, his Yorozuya cohorts, have had a falling out and are now battle-hardened solo vigilantes and he himself has been missing for years, disappearing without a trace after scribbling a strange message in his journal. Setting out in the disguise given to him by the android time machine, Gintoki haphazardly reunites the Yorozuya team to investigate the White Plague, and soon discovers that the key to saving the future lies in the darkness of his own past. Determined to confront a powerful foe, he makes an important discovery—with a ragtag band of friends and allies at his side, he doesn't have to fight alone. [Written by MAL Rewrite]

A letter arrives at Death Cram School. Inside is a an invitation to a spa resort. Yumi declares to the four excited girls that, "No. This is evil itself," points out that they are slacking off too much. Shiki proposes, "When opinions are divided, it's time for boob rock-paper-scissors!" and then wins so they all go to the pool. There, girls from Hanzoo Academy, Homura Crimson Squad, and Hebijo Clandestine Girls' Academy also come, but Asuka says, "Let's have fun together today" and they call a temporary truce. However, a trivial matter sets off a sour quarrel and, at Yumi's suggestion, they settle it with a showdown in the style of the ancient shinobi. (Source: ANN)

Azmaria Hendrick gives some background information on characters and the setting, with flashback scenes from the Chrno Crusade series itself. Released with DVD volumes 2-12.