The story begins with Masaki Michishita, an ordinary prep school student who is rushing to the bathroom in a park one day. Despite his rush, he spots Takakazu Abe, an exceedingly handsome auto mechanic sitting on a bench. The two exchange looks, and after Abe utters "Yaranai ka" (Shall we do it?), the two begin their encounter.

A project to commemorate the 10th Anniversary of Tsukiuta. The Black Rabbit Kingdom and the White Rabbit Kingdom — Two different worlds existing side by side. The two worlds, which were supposed to be a "pair," had never met, perhaps by a twist of fate. The situation remained unstable and incomplete. Hajime, the young king of the Balck Rabbit Kingdom, is distressed by the calamities in the surrounding countries. The Prime Minister Haru, his close aides Kakeru and Koi, the prince Aoi, and his escort Arata are busy preparing for the upcoming World Congress and the ball to commemorate the 15th anniversary of Hajime's reign. At the same time, in the White Rabbit Kingdom at the suggestion of Shuno, who calls himself the Demon King, the king, Kai, the prince, Rui, the guards, Yoh and Iku, and the former military officer, Yoru, are going on a "picnic" to the Black Rabbit Kingdom. What will be born from the encounter between the Black Rabbit Kingdom and the White Rabbit Kingdom?

A compilation film of the Courtesan of the Nation Arc, episodes 5–9 in the third season, featuring additional footage. The movie is a part of the "Gintama 20th Anniversary Project."

Business is slow for the Ootsuji Detective Agency. Soutarou and his juvenile sidekick Saki will take any job that comes along, even one that sounds like a lot more risk than it’s worth. It’s festival season in the city but away from the public eye, a wave of mysterious disappearances has occurred. A newspaperman hires Soutarou to investigate, suggesting that answers might lie somewhere in the Dark, the notorious, anarchic maze that is the city’s physical, social, and moral underground. Soutarou subcontracts the gig to Saki, but soon enough regrets it when the kid also goes missing. Now Soutarou is obligated to venture into the Dark himself, and confront its dubious subterranean denizens, including the malicious Laughing Masks gang and the renegade police squad piloting the fearsome Demon 463 armored train!