Naibara Hirokazu left his parent's home in Miyagi to attend university in Tokyo and began living alone in an apartment in Saitama. Soon after moving, he answers a phone call from an unknown number that rings repeatedly, and hears a girl's voice saying

"I'm Mary, I'm at the garbage dump right now... I'm the doll you threw away..."

Thinking it's a prank call, he hangs up, but the call comes again and again... It seems like the girl is calling little by little, moving towards him!? The next day, he answers the phone, not knowing how many times it has already been called, and hears

"I'm Mary, I'm in front of your room right now..."

No sooner does he hear a strange voice praying from outside the apartment...? A phone call from Saitama to give advice to Mary, the urban legend who has been transported to another world!? A little girl connected by smartphone to a university student's story of defeating the demon king!!

(Source: Gamma Plus, translated)