On his first day at his new school Jake Jones meets the new teacher, Mr. Hyde (very nice, but turns into a naughty imp when upset), Mrs. Blount, the principal (a nasty tyrant whose punishments involve hard labor), and his wild classmates in 5B--and since it is almost impossible not to break at least one of the 142 school rules (or all of them) he soon finds his school life descending into chaos.