What kind of title is this?: Manga.
How many volumes are there?: 3 volumes are listed.
How many chapters are there?: 15 chapters are listed.
Where can I read it?: Reading links are listed for Official Site, Kodansha USA. Check availability in your region.

Synopsis

About Suzume

High school junior Suzume has no idea why the beautiful stranger she meets is looking for ruins, for a certain door. Soon after pointing the stranger, Souta, in the direction of an abandoned resort, she thinks better of it and goes to try and stop him. But before she can find Souta, Suzume unknowingly opens a decrepit door to a world beyond time and place—and stumbles into an adventure of seismic proportions. (Source: Kodansha USA)

Fantasy