Kyoko Okitegami (Yui Aragaki) is a private detective. She is known as the Forgetful Private Detective. When she wakes up in the morning, her memory is reset. Due to this, she rigidly adheres to a maintenance secret. No matter what case she has, she has to solve the case in a day. On her body, she has an important note that she must never forget.
Even though Yakusuke Kakushidate (Masaki Okada) has a crush on Kyoko Okitegami, he is alway mistaken as the culprit of a case by Kyoko Okitegami. No matter how close Yakusuke Kakushidate gets to Kyoko Okitegami, she totally forgets about him by the next day.