幻日のヨハネ -NUMAZU in the MIRAGE- is a deck-building rogue-lite game set in the universe of the popular Love Live! Sunshine!! series. Players assume the role of Yohane, who, while working as a fortune teller in Numazu, stumbles upon an ancient mirror that transports her to a mirrored version of her world called "裏ヌマヅ" (Ura Numazu). This new realm allows players to harness the power of cards for magical battles, as they navigate through challenges to rescue friends affected by strange occurrences.

The game features over 150 unique cards, enabling extensive deck customization. Players can summon powerful allies using "召喚カード" (summon cards) to aid them in their adventures. The game's structure includes a dynamically changing map, ensuring that each playthrough offers new experiences and strategies. Additional features include a fortune-telling booth for character upgrades and a closet for costume changes that alter initial cards and charms, enhancing gameplay possibilities.