Kagura Reimeiki ~Ryouka no Shou~

Ryouka travels to find Tome-sama who disappeared with Mikoto. While investigating, Ryouka enters a bamboo grove where suddenly she is enveloped in a light and disappears while pronouncing Mikoto's name.

After that, Ryouka loses her memory and faints. Waking up with no memory, she arrives at a shrine where she is cared for and looked after. One day the shrine receives a request to investigate the ancient shrine of the Dragon God where suspicious disappearances have begun to occur.

Ryouka upon learning of this accepts the request and goes to investigate the ancient shrine. https://www.debonosu.jp/debo/game/reimeiki_22/index.html