A sudden mouse infestation at Night Raven College inspired Epel to make a mouse-warding potion. While holding the potion he collides with Trey (carrying a box of Science Club potions), Jamil (carrying fireworks) and Silver (carrying a potion for an assignment), with the combination of the different ingredients producing a potion that shrinks them down to 1/22 size.
The group crafts clothing for themselves. As the potion may last “anywhere from a week to 10 days” but they do not want to reveal to other students or faculty what has happened, they decide to create a neutralizer potion to counteract the shrinking effects. While collecting ingredients from the school kitchen Grim eats fruit, covering himself in fruit juice.
When ghost chefs enter the kitchen Epel attempts flight magic to escape, but is unable to fly on his sewing pin.
In the school’s courtyard a bat kidnaps Grim and the prefect, with Epel guessing that the bat has mistaken the fruit-juice-soaked Grim for fruit and intends to try and eat him.
Trey, Silver, Jamil and Epel are knocked into the sewers by Lucius, where they discover a fake mouse used in animal linguistics classes, as well as real mice. Epel wears the fake mouse’s ears and tail when communicating with the real mice.
Trey translates for the mice, saying that the bat that kidnapped Grim and the prefect is notorious among mice: he recently abducted a younger mouse’s father, and they have all come to Night Raven College to rescue him.
The mice offer to guide the group but, in exchange, the students are to confront the bat, and Epel agrees. They reach Grim and the prefect who then get taken away again by the bat, and Epel again fails to use flight magic on his sewing pin.
The group takes balloons intended for an upcoming party, a dishcloth and cutlery box to fly in pursuit of the bat, whom Epel jumps at in midair.
A hole gets torn in one of their balloons and the group is sent crashing into the school’s clocktower, where the bat attacks them.
Epel falls from the clocktower with the bat, but saves himself by finally using flight magic successfully on his sewing pin. When the bat begins attacking Epel in the air, the school’s clocktower begins to ring, immobilizing it.
Epel tackles the bat, sending it falling, and the kidnapped mouse is reunited with his daughter.
Silver and Jamil briefly get stuck in an adhesive mousetrap but free themselves with oil, and the group then takes their neutralizer potion.
It is revealed that Rook discovered Epel’s discarded school uniform, with a note he left behind possibly insinuating that he assumed Epel had taken off his clothes to enjoy the rain.
