The book details a fictional college where absurdity and awful puns are the order of the day; its students range from witches and werewolves to secret agents and space aliens.

Adventures can involve joining fraternities, surviving dorm life, dealing with rampaging lab accidents, conquering other worlds on field trips, getting caught up in faculty bloodfeuds and even attempting to pass a class.

Due to the extremely dangerous nature of the academic work done at IOU, many of the staff undergo The Treatment, a mysterious and dreaded procedure that makes them virtually unkillable and thus immune to their own recklessness.

There are rules to such conflicts (Faculty Bloodfeuds), one of which is that "freshthings" in their first semester are off-limits and harm done to them will attract the unfavorable attention of the Archdean.

Basically, IOU is a glorified joke book, a drop of Monty Python mixed with a bucket of Three Stooges.