Set after the time of Sakura Taisen 4 (game), Kanzaki Sumire, during a training session was noticed that her spirit power (rei-ryoku) has dropped tremendously, below levels required to pilot the Koubu-nishiki. She decides to retire from the Kageki-dan while she still holds the position of "top star" in the dai-teikoku gekijyou.

Specials included with the Blu-ray box set releases of Joker Game.

The Cleopatra Corns Group, aka Cleopatra DC, is a powerful financial conglomerate controlling most of the United States economy, almost as powerful as the US government itself. At the top of the organization is the beautiful, smart and brave Ms. Cleo, the Group's young, talented Chairman. This is good--it means she can handle the repair bill when that airplane crashes into her bedroom. With stolen artifacts, corporate kidnappings, and top-secret cyborg projects gone awry, her luck only gets worse from there.

Angels from the planet Eden have been watching Earthians, the inhabitants of Earth, for 5 billion years. Chihaya, an angel with unlucky black hair and wings, is a plus checker who travels to Earth with Kagetsuya, a minus checker. Each team of plus and minus checkers keep track of Earth events and, if the score ever reaches minus 10,000, the Earth will be destroyed. The story follows Chihaya and Kagetsuya and the different people and events they observe on Earth.