Since her childhood, Suzu has seen creatures that no one else can see, and she has naturally interacted with them, as if they were friends.
Although, the rest of her classmates avoid talking to her, considering her weird or crazy, Matsuri understands how she feels, after all, he can see the creatures as well.
As the years pass, the children grow up, and one day, without warning, Matsuri tells Suzu that she must stop making friends with magical creatures, or ayakashi.
Matsuri’s family is part of a clan of exorcists who destroy the evil ayakashi of the town, and now that Matsuri’s grandfather considers retiring, he informs his grandson that Suzu could be in danger once she grows up
But instead of telling Suzu the truth, Matsuri decides to drive away, and even exterminate, the ayakashi who often get close to his childhood friend.
Years later, Suzu enjoys eating some crepes while Shirogane, a strange cat-shaped ayakashi, watches her from a distance and thinks that she looks delicious.
But before he can do anything, Matsuri appears and intercepts him. Shirogane doesn’t hesitate to threaten the boy, reminding him that he has been on earth for over 400 years.
In the commotion, Suzu appears and starts berating Matsuri for mistreating Shirogane, she immediately recognizes him as an ayakashi, and Matsuri tells her he might seem harmless, but he was plotting to do something to her.
The girl does not listen to Matsuri’s warnings, and tells him that she will release the cat in a safe place.
On the way to a temple, Shirogane takes the chance to ask her about her relationship with the ninja. and Suzu tells him that Matsuri helped her a lot when they were kids, but when he became a ninja he changed drastically.
Suzu begins to talk about her relationship with Matsuri, and that now that they are entering high school, they should behave more maturely. Shirogane begins to think that she is eager to find romance, how much he despises humans and that he won’t allow it, because he intends to devour her.
Meanwhile, at his grandfather’s house, Matsuri tells him what happened with Suzu, and when he mentions the cat’s name, he tells Matsuri that his friend is in danger, that such ayakashi is quite powerful and is capable of hiding his true identity.
Matsuri runs off to find Suzu, whereas Shirogane tells Suzu that she possesses a very rare power, and that the amount of energy she emits is so special that any ayakashi would like to feed on it.
Shirogane transforms and tells her that she will help him power up her considerably, but before he can devour Suzu, Matsuri appears and starts fighting him.
At last, Suzu seems to understand why Matsuri changed his way of being, and why he tried to prevent her from being in contact with the ayakashi.
Taking advantage of his surprise, Matsuri uses a scroll from his grandfather, powerful enough to seal Shirogane. Observing what is going on, Shirogane can’t stop thinking that Suzu and Matsuri could end up dating, and he decides to curse the boy and transforms him into a woman.
From that moment on, Suzu’s life, and especially Matsuri’s, has a new beginning.