In a medieval land where a country's power and prosperity depended on mahjong-playing skills of its inhabitants, the Darol army began an invasion campaign, aided by demonic forces. The Kingdom of Rida was conquered. The young royal guard Biares fought valiantly, but was unable to defeat his mysterious opponent in mahjong. He was teleported far away, and found by a girl named Olivie. Biares has to find a way to return to Rida and liberate his country from invaders, finding companions and playing mahjong on the way.

Seisenshi Densh?: Jantaku no Kishi is a mahjong game. The story mode features extensive cutscenes and dialogue between mahjong matches. Mahjong gameplay itself is of the one-on-one variety; a few rules regarding combinations and bonuses can be customized. The free mode allows the player to match Biares against various characters encountered in the story mode.