The heroine of this curiously named title is Choko, the princess of the fictional country Baskin, which is mostly a medieval world with some modern-day anachronisms. She lives in the capital city Robins with her Mom and Dad, namely queen and king. Her curious nature eventually leads her to some interesting acquaintances, including magic users and adventurers, who help her to uncover a threat to her family and country. The princess has to travel through a dangerous forest with her best buddy Meron, in order to protect Baskin from danger.
31... is a Japanese-style adventure game. The interaction is minimal, usually restricted to two or three commands (mostly Look or Talk) with a few sub-menus at most. Usually, the player advances the story and proceeds automatically when all the options at the screen are depleted. However, there is also menu-based navigation (in the forest, etc.), which requires memorizing ways and choosing directions correctly.
The game contains scenes with nudity and sexual situations.