Okitegami Kyoko is a beautiful private detective who has a deep love for money. She is also known as the Forgetful Detective. Her memory is reset when she sleeps at night, which means she can strictly adhere to confidentiality requirements. She solves all her cases within a day, whatever they may be. She is the world's fastest detective! There is something really important that Kyoko must never forget, and it is written on her body with a magic pen.

“I am Okitegami Kyoko, detective. My memory is reset after one day.”

Meanwhile, even though Yakusuke Kakushidate has a crush on Kyoko Okitegami, he is always mistaken by her as the culprit of a case. No matter how close he gets to Kyoko, she totally forgets about him by the next day.