New cadets arrive at the Metropolitan Police Academy, now under the leadership of Commandant Hefilfinger. The cadets must rescue their hard-nosed instructor Sgt. Ledbetter, after he is kidnapped by a biker gang.
In a training exercise staged for the cadets, Casey plays the role of a criminal on the loose. But confusion arises when a Casey look-alike escapes from prison. The Tackleberrys adopt a pet pig.
The arrival of a filmmaker filming a recruitment video gives Ledbetter the opportunity to record proof of Casey's shenanigans. The Tackleberrys care for an infant left at their door.
Expecting a delivery of an exercise bicycle, the Commandant receives an Egyptian mummy instead. In an attempt to impress her strict father, Annie pretends to be a drill instructor.
While on a stakeout at the beach, Casey becomes involved with an attractive TV star who is kidnapped. Annie fears she may have a curse, and visits a psychic for help.
Casey is stalked by a woman obsessed with marrying him, just as romance is blossoming between Casey and Annie. After a knock to the head, Lester develops multiple-personality disorder.
With the cancellation of summer vacation, Hefilfinger and the cadets try to get their Christmas shopping in early, but find themselves held captive by a group of inept thugs.
Police Academy court is in session. With Hefilfinger as judge, and Ledbetter as prosecutor, Casey is put on trial for allegedly assisting a bank robber.
Eric Lassard comes out of retirement to fill in as Commandant, while Hefilfinger takes a refresher course. Ledbetter experiments with a new hair-growth treatment.
Captain Hightower returns to the Academy to train the new cadets, and to receive an award as "Alumnus of the Year", while also lending Casey a helping hand in tracking down an armored car thief.
The Commandant's pet turtle, Zeus, becomes possessed by a creature from outer space. Ledbetter attempts an Academy takeover. Lester teams up with Cassandra to catch a thief.
Lester joins a dating service, using Casey's photo on his profile. Jones tutors the cadets on how to detect a pickpocket. Luke becomes a game show contestant.
Hefilfinger organises a Cadet of the Year competition to increase the number of Academy enlistments, but Ledbetter does his best to keep Casey from winning. Due to budget cuts, Commissioner Hurst is named the new Commandant.
Ledbetter and the cadets embark on a ski trip for winter break. Alice & Annie have the hots for a handsome concierge. The Tackleberrys try befriending Lester. Casey meets the love of his life, but has trouble being accepted by her father.