Ephemeral Fantasia is a Japanese-style role-playing game set in a fantasy world. The story follows Mouse, a silent musician who plays with his talking guitar Pattimo, as he travels to the island of Pandule to play at a royal wedding. However, upon arrival, Mouse discovers that the groom Xelpherpolis has cast a time-looping spell on the island, intending to destroy its population. With the help of some new allies, Mouse must break the spell and stop the villain.
The gameplay in Ephemeral Fantasia is turn-based combat with several characters that can be recruited to the party. The game features a unique time-looping system, where an internal clock creates a repeating cycle of five days. Players must navigate the island at specific times to trigger certain events and progress through the story.