A direct sequel to Jantei Monogatari 2: Uch? Tantei Divan - Shutsud?-hen, the game continues the overarching plot, following the events of the previous game. The evil alien Dora and his sexy female demonic minions are descending on Earth, sending their subordinates to stop Divan and Marie. Divan must use his robot transformation abilities to defeat them, which can only be done when playing mahjong.

The mahjong gameplay in this installment of the series is identical to that of its predecessor, including points distribution and execution of powerful transformation moves to gain the upper hand in the round. Unlike the previous games in the series, this chapter eschews the rudimentary adventure gameplay, featuring long non-interactive cutscenes between mahjong matches. Another change is the addition of a new mode that allows the player to compete against opponents from the story mode at any time, without going through the story.