Mephisto III is a half-human and a soon as he wakes up finds out that Akuma-kun ate his ramen. They get into an argument, and Mephisto III knows he will never win, Akuma-kun is quite stubborn and takes a logical approach to everything.
Actually, Akuma-kun is supposed to be a genius that appears once every 10,000 years.
Later, Hina, a college student, enters Akuma-kun’s office and starts telling her story. Although he isn’t initially interested in her case, Akuma-kun finds it curious the more she explains it.
Two of her friends died at the same time in different locations. And, when she went to their funeral, she found out the same thing happened to other three people.
Akuma-kun and Mephisto go to Hina’s house to investigate. And without filters he enters her house and demands her mother to bring him hotcakes, not pancakes, and he gets into an argument about what they are with her.
After he eats, he listens to the rest of the funeral’s story. Each death happened in different ways too, from suicides to accidents.
When Akuma-kun starts his investigation, he finds out a creature below Hina’s bed. He doesn’t show his surprise, just gets up the floor, draws something on a piece of paper, and asks to Hina to hang onto it while sleeping.
At night, the monster shows up and crawls below her bed, trying to attack her while she sleeps.
However, Hina is able to understand what is going on and rushes to grab the piece of paper that Akuma-kun gave her. As the creature disappears, she thinks it was just a nightmare.
Then, once the three of them meet, Akuma-kun explains what he found out. He says the locations where the people died form a a pentagram figure. And thinks it’s used to protect something at the center, he just doesn’t know what it is yet.
Then, Hina says it’s the house of Ichika, a friend of hers from college. She tells them the girl hasn’t shown up to class in a while and no one has seen her anywhere.
Before saying goodbye, Akuma-kun warns Hina she should have the warding symbol close to her. At night, the monster tries to attack her once again but is dispelled.
The next day, Mephisto and Akuma-kun talk about families. Akuma-kun says he hasn’t seen his dad in a long time. When they reach their home, they see Hina talking to Mio, their landlord’s daughter.
The three of them go to Ichika’s house, where Hina tries to talk to her while Akuma-kun draws a spell on the floor.
When the door opens, Ichika is levitating and turns into the monster. She attacks them, but Akuma-kun helps Mephisto summon an attack that electrifies her.
However, that doesn’t seem to work as expected, and Ichila charges at them again. But before she lands her attack, someone with a bright yellow cape saves them.