You know that awesome movie or book that becomes a sudden best-selling blockbuster? Everyone loves it, so what’s the next thing that happens? Yep – a sequel. And frequently, the sequel is nowhere near as excellent as the first one. Sometimes, if the sequel isn’t a total bomb (or even if it is), then an entire series is spawned out of something that probably should have remained a one-shot. (Anybody remember sequels that shouldn’t have happened, like Jurassic Park II and III, or many of the Disney animated direct-to-video sequels of the 90s?)

This is known as “sequel syndrome,” and it’s not actually something created by Disney or 90s adventure movies.It’s been a thing for about as long as we’ve had commercial entertainment. Decades ago, just like today, there were some mediocre sequels, some sequels that never should have happened, and some really stellar sequels that made the series into a win.

One of the hallmarks of sequel syndrome is to capitalize on the elements that made the original popular. If the first book or movie is funny, then the sequel is funnier. If everybody loved the sinister villain, then add more sinister villains to the next story. The monsters in movie number one were popular, so movie number two must feature twice as many monsters that are twice as monstrous. This technique is often what makes the sequels fall flat – they’re more like caricatures of the original, instead of an effective continuation.

But not all sequels have to succumb to the bad side of the syndrome and leave a bitter taste in our mouths or crummy numbers at the box office. There are approximately 271,098,335 stories that I could use for this example, but I’m going to focus on just two series. And to prove that sequel syndrome wasn’t spawned by the TV movie age, I’m going to discuss two series from the early 20^th century.

The Wizard of Oz

To illustrate the negatives of sequel syndrome, I’ll use the Oz series by L. Frank Baum. Now first let it be known that I’m a huge Oz fan, and I love all of the books. But in my opinion, Baum succumbed to several negative aspects of sequel syndrome as he wrote his 14 Oz books.

The Oz stories, being fantasy, of course feature amazing creatures, monsters, and magic of every sort. These fairy-tale elements – like a scarecrow that was brought to life, or a city made entirely out of emeralds – are what made The Wonderful Wizard of Oz so popular.

So in many of the subsequent books, the fantastical world was the main focus – and often, the only focus. In several of the books, there was no plot to speak of – the story was simply a wandering journey through magical oddities. A city of china dolls is entertaining – so how do you top that in a sequel? Have a city of paper dolls, of course. Or a city of talking silverware. Or a city of people who have roller skates on their wrists instead of hands.

I’m not trying to put down Baum’s creativity – and the Cuttenclip city (the paper dolls) and the Wheelers (the roller skate people) were popular enough to keep Baum writing more and more books. But many of these wild fantastical creations became absurd as the series progressed, and things like plot and character development were often sacrificed in the name of “new fairy land adventures.”

Sure, there are worse sequels than the random, wandering Road to Oz (book #5 in the series). And I still love all the Oz stories – as does the general public, even today. (Wicked, anyone?) But from a storytelling standpoint, the Oz series demonstrates the problems inherent in sequel syndrome.

This isn’t so much of a sequel, as simply an adaptation. No Judy Garland songs or Technicolor Munchkinland in this version, though. That’s right, kids – even back in 1910 the modern marketing engine was going strong.

The Thin Man

In 1934, Dashiell Hammett published a novel titled The Thin Man, and that same year it was made into a movie. It’s a comedic murder mystery, and the main characters are a retired detective and his wife, who spend as much time drinking and being snarky as they do investigating the murder case. Because of the popularity of the first movie, five more films were made.

What was it that made the first movie such a hit? In addition to the onscreen chemistry of the two stars (William Powell and Myrna Loy, for anyone who wants to know), it was primarily the witty dialogue and the comedic use of alcohol. The plot was also engaging, worthy for any fan of Agatha Christie-style mysteries.

So what could have happened in a sequel? Focus on the most memorable aspects of the first movie – Nick and Nora’s banter and their use of alcohol. The sequels easily could have dissolved into drunken snark-fests, with a vague backdrop of a plot-hole riddled mystery story. But they didn’t.

The writers of the films (the original book’s author contributed to some of the screen plays) were masterful at not falling prey to sequel syndrome. The characters maintained consistent behavior throughout the series (snark, drinking, and crime-solving in equal parts). The plots, while all following the standard mystery trope, were consistently strong, and were never sacrificed to the comedy. From a storytelling perspective, the Thin Man series rose above the potential pitfalls of sequel syndrome.

The witty banter and frequent drinking were comedic elements in all of the Thin Man movies. This easily could have been overdone, but it wasn’t. In one film the characters stayed dry the whole time, but the plot, characters, and comedy didn’t suffer.

If you’re writing a sequel or a series, what are some of the strongest elements of the story? What can you do to make sure that the next in the series is just as strong as the original?