This Starry Midnight We Make

"Hamomoru Tachibana, our protagonist, is an overly serious, easily-flustered clergywoman. While on vacation in Kyoto, Japan in the early 20th century, she went to visit a night festival at a local shrine. While enjoying one of the local specialties, she found herself lost in a deep forest road near the shrine.

In the depths of the forest, flanked by a trio of archways, Hamomoru meets Chuuya Shingoh, a curious, self-professed student of sciences. Chuuya shows Hamomoru the "Star-seeing Basin", wherein one can seem to "grow" stars and a model of the night sky using pebbles, and invites Hamomoru to join his experiments. She is hesitant at first, but her missing wallet compels her to remain in Kyoto regardless.

Ultimately accepting Chuuya's offer to help with lodging, she agrees to assist him in his "research" in return. According to Chuuya, the stars created in the Basin may be able to influence the rest of the city in a manner similar to what is often described in onmyou divination. To confirm this, Hamomoru and Chuuya shall walk the streets of Kyoto, all while creating stars within the Star-seeing Basin..."