From Bulbapedia, the community-driven Pokémon encyclopedia.
Michīna (Japanese: ミチーナ) is the setting for Arceus: To a Conquering Spacetime.
Michīna is a riverside town surrounded by flourishing nature. The town's centerpiece is the Michīna Ruins.
Thousands of years ago, Michīna was a desolate place, which was nothing but a wasteland. But the Jewel of Life's power that Arceus gave Damos made the town's soil rich and fertile.
The Michīna Ruins are old ruins of a temple, located at the peak of a huge, rocky mountain in Michīna. Beside the ruins is a beautiful lake.
The ruins are guarded by Sheena and Kevin. It is where Damos witnessed the awakening of Arceus. It is also the home of the Jewel of Life. The Space-Time Model can be found in the basement of the ruins.