The 13th Footprint, Vol. 1 (Hardcover) (manga)

Following their son Ao’s release from the hospital, Touya, Haru, and Ao were all ready to start a new life in their picturesque new home. But that was before the postcards arrived… Each postcard details an event—one that won’t happen until the next day.  Follow this family on an adventure to unravel the mystery, stopping to help everyone they can along the way.