An ordinary school day turns into a fantastic adventure for Petya, Marusya, and Vasya when their idle time becomes the source of power for three old wizards. In pursuit of youth, the villains steal the students' time with a magical gadget, but in their haste, they themselves turn into children, and the children into helpless old men. To set things right, they must not only win the magical battle but also lift the spell before sunset, and most importantly, understand the value of every wasted minute.