Movie sequels are like pie.

Really.

After a film enjoys marginal box office success and a handful of friendly reviews, the producers and writers take the leftover dough from the first film and begin to roll it out for a sequel.

But the little bit of dough left from the first film gets stretched too thin, making it crack and fall apart, resulting in nothing more than a big mess. And like most sequels (with the exception of “The Godfather” and “Jaws”) “Bridget Jones: The Edge of Reason” is a huge mess.

The sequel to 2001’s “Bridget Jones’s Diary” picks up right where the first one left off: with Renee Zellweger as Bridget — finally in a happy relationship with Mark Darcy, played again by Colin Firth. Where the first film focused on the neuroses and tribulations of the average, slightly overweight, single girl, the sequel focuses on the neuroses and tribulations of the average, slightly overweight girlfriend. But then Bridget breaks it off after she and Mark have a fight, and she spends the duration of the film figuring out where she went wrong. And that’s really pretty much it.

No dough, no plot, total disaster.

As the film progresses, it becomes more and more obvious that director Beeban Kidron had no idea what to do next. And with every desperate attempt to thicken the plot, the story just unravels and becomes more irritating. Shipping Bridget off to Thailand on a news assignment — and the coincidence of Daniel Cleaver (Hugh Grant) there with her — is not interesting and juicy; it’s ridiculous.

As if the whole Thailand fiasco isn’t bad enough, some creative genius decided it would be an interesting and believable twist to have Bridget get caught with cocaine and sent to a Thai prison, where she will wear her bra outside her shirt and gossip about boys with the other female inmates. This is where the film goes completely to hell. It is as though Kidron has taken a three-week coffee break and left the film in the hands of an intern at Miramax.

While the story spirals further downward with every scene, one element does remain somewhat consistent from beginning to end — Zellweger’s performance as Bridget is awkward and distracting. In the first film, Zellweger’s significant weight gain was more of an afterthought that made her character more realistic and relatable for young female viewers. In the sequel, her weight is its own character. She waddles like a penguin and thrusts her belly forward like a four-year-old showing off the result of three months of hard work eating Krispy Kremes. Zellweger portrays Bridget in the sequel like a “Saturday Night Live” parody of herself, rendering her performance unconvincing and irritating.

All in all, there were simply not enough leftovers from the first “Bridget” to make a satisfactory sequel. The only genuinely amusing moment in the film is the fight between Colin Firth and Hugh Grant in which they slap each other silly like sissies.

“Bridget Jones: The Edge of Reason?” More like “Bridget Jones: The Brink of Total Chaos.”