If there's a rule that dominates Hollywood, it's that money talks. A successful project will be imitated, its stars and crew will become hot commodities and a sequel (or maybe six) will get made.

But if there's a law that governs Hollywood, it's that nothing lasts forever. Eventually, the money train always runs out of steam. Even the most successful properties reach a point where the spark fades, and they stop earning the kind of returns that attract investors and star talent. From then on, it's only a matter of time until their extinction. In the Police Academy franchise, that turning point came on March 18, 1988, with the release of Police Academy 5: Assignment Miami Beach.

The first Police Academy movie was a hit in a year that has become synonymous with the kind of massively profitable movies the '80s were famous for producing: 1984. Like a cheeky, cheesy interloper in a land of cinematic giants, it sprang up among the likes of Beverly Hills Cop, Ghostbusters, The Karate Kid and Gremlins, ranking as the sixth highest-grossing film of the year (on a budget of a mere $4.5 million) and outperforming what most people would consider far superior movies in Footloose, Romancing the Stone, Star Trek III and Splash.

It was a surprise hit made on the cheap, and the producers, led by Paul Maslansky, immediately made the call to begin cranking out sequels at the pace of one a year. They released these in the spring, during the dead time between awards season and the summer blockbusters, and made sure that none strayed too far from the pattern laid down by the first movie. It was a remarkably effective formula, and the first four films all reached No. 1 at the box office.

In essence, the movies were a mash-up of the broad comedy successes of the decade that preceded them, mixing the "charming band of losers takes on the establishment" trope perfected by Animal House (1978) with the absurdism pioneered by the Zucker/Abrahams team in films like Airplane! (1980). They had a charming, hangdog protagonist in Steve Guttenberg, a trope that kept on giving – inept police cadets becoming actual officers and then bumbling their way into solving crimes – and just enough raunchiness to titillate the teenage audience.

And then came 1988 and Police Academy 5. Like all four of its predecessors, it was the No. 1 film in the U.S. on the weekend it opened, and it earned almost $20 million against a budget of $6 million. The reviews were terrible, but then again, the critics had always hated the Police Academy movies. (Roger Ebert memorably said of the original, "It's so bad, maybe you should pool your money and draw straws and send one of the guys off to rent it so that in the future, whenever you think you're sitting through a bad comedy, he could shake his head and chuckle tolerantly, and explain that you don't know what bad is.")

Watch the Trailer for 'Police Academy 5'

The plot centers on the befuddled old commandant of the Academy, Eric Lassard (George Gaynes, doing his best Leslie Nielsen), who is being forced to retire because he's too old. However, on the way out he's being honored in Miami. So he brings both his allies (the crazy crew of cops that has populated the first four films) and his enemies (namely Captain Harris, played by G.W. Bailey, who has always wanted his job) to the celebration with him.

But during the trip, Lassard manages to end up in the possession of a bag of jewels from a recent heist, which results in him being kidnapped by the jewel thieves. This necessitates a rescue by the Police Academy gang in a pretty by-the-numbers "action" sequence (which, incidentally, contains the one really good moment in the movie: a great live-action motorcycle stunt). In the course of this mayhem, Lassard proves that he's still got it by disarming the main bad guy. The film ends with Lassard reinstated, the gang happy and Harris getting his comeuppance, which involves a gag in which he flies through the air and gets his head stuck in a big marching-band drum.

On the surface, this is all pretty standard Police Academy fare. But beneath this, things were changing, and not for the better. Guttenberg, who had good-naturedly anchored the first four entries, had jumped ship to shoot Three Men and a Baby and would not return to the franchise. His screen presence and easygoing charm are badly missed in the film, and his replacement, Matt McCoy, playing Lassard's nephew, never quite manages to get into the rhythm of the comedy (such as it is).

Beyond this, though, the film makes a clear turn away from the teenage raunchiness that helped propel its predecessors to success and makes a clear turn to silliness. The gags don't have even the whiff of schoolboy transgression that had managed to titillate audiences for half a decade, and the movie feels closer to Disney's heartwarming '80s films than it does to Bob Clark's Porky's, which was one of the clearest influences on the original Police Academy.

The franchise didn't give up without a whimper or two. A pair of sequels followed, Police Academy 6: City Under Siege (1989) and Police Academy: Mission to Moscow (1994), and there would eventually be a pair of TV shows that attempted to carry on the dream. But after Police Academy 5, the fairy dust finally wore off. The profits declined, and the investors who make Hollywood work looked for other projects.

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