Ms. X, famous investigator, is going through a rough patch. Since she was stung by the nap fly, she can’t solve a mystery without falling asleep in the middle of the crime scene. And everything gets worse when, due to a misunderstanding, she starts teaching in after-school activities. Anyway, while she is not a normal teacher, her pupils aren’t normal students either. Lena, Alex, Bruna and Henry soon decide to turn the after-school course into a detective agency, where Ms. X will be able to get her prestige back while the children have fun solving mysteries.