'The really irritating thing about a novel," says Dave Barry, "is you have to have a plot."

The much-honored funnyman, who got his start as a journalist in West Chester, then found a home - and a trove of great reporting and humorous columns - in South Florida, has a new novel, Insane City, his first solo novel in 10 years, on sale Tuesday. It does have a plot, a pretty funny one. Barry reads from it at the Free Library at 7:30 p.m. Thursday.

Barry wrote his syndicated humor column for the Miami Herald from 1983 to 2005. He says, "A year spent writing a novel is way, way harder than a year writing columns. Way. You can't get by just telling jokes. You have to make characters and have them do something. And that, I gotta tell ya, is a pain."

The publicity for Insane City calls it a "dark" comedy. Nonsense. It is, like most Barry productions, rib-splittingly funny, a mixture of social criticism and just plain silly stuff.

There's even an orangutan named Trevor, OK?

Insane City does, however, have something new to Barry novels. At the nougaty center of this comic candy bar there's an almond of seriousness.

"Of all my books, this has got the closest thing to a plot with some weight to it," says Barry, by phone from his home near Miami. "It's always my main goal to make it funny. The novelist I most admired as a kid was P.G. Wodehouse, which was all about banter, with wacky characters bouncing off each other. There was rarely anything meaningful going on. But I was happy to find Laurette and her children and give Seth a dilemma."

The momentarily almost-serious heart of Insane City involves Seth Weinstein, a guy from D.C. with the ultimate slacker job: He sends out product ads from anonymous Twitter accounts. His fiancee, Tina, says, unkindly, that he "tweets about douche."

Seth is in South Florida for his worst-idea-ever wedding to Tina, a high-end, edgy Mistress of the Universe. He gets hammered with his posse and passes out on the beach. When he wakes up, he sees Laurette and her children clinging to a capsized boat. He dives in and saves them. They're, uh-oh, refugees from Haiti.

"Seth is forced to become a person. He's never had to deal with a situation that's about somebody else's needs," Barry says. "So this is a novel about a wedding that gets interrupted, both the novel and the wedding, by a dilemma involving immigration."

"I'm not preaching anything here," Barry says. "Immigration . . . I have no idea. I feel a right and wrong in there somewhere, but I have no solution. I'm like Seth: I look at it as a human situation."

And there's also a python named Blossom, OK?

Insane City sends up the nuts ritual the Great American Wedding has become ("which I learned," Barry says, "watching my son get married"), and it also revels in the hideous comic nightmare that is Dave Barry's South Florida.

"I contend," Barry says, "that South Florida is the most surreal place in the United States. There's no other place so consistently weird and exotic." He quotes his friend, the fellow journalist and author Carl Hiaasen: "He once said something like, 'If you live in Miami, you don't need an imagination, just a subscription to the newspaper.' "

Mind you, when Barry used to live in Philly, "that was a pretty funny place, too, what with the people you had running things up there - Frank Rizzo and Wilson Goode. 'I know - let's have a helicopter firebomb a rowhouse.' "

A Haverford College grad in English, Barry worked at the West Chester Daily Local News from 1971 to 1974, and also in the Philadelphia bureau of the Associated Press before heading for more humid climes. "I still think of myself first and foremost as a journalist," Barry says. "It's the best possible training you could ever have if you want to be a novelist."

Barry's novel follows by a few months Tom Wolfe's Back to Blood, another comic novel set in the multicultural brew of South Florida - Haitians, Russians, Cubans, white power elites with "a lot of money but never enough," in Barry's words. Oh, yes, and alligator farms, stoners, mobsters, Everglades cowboys, reptiles, and primates. Like Trevor.

Hiaasen's young-readers novel Chomp came out last year, and it has a lot to do with zoos, too. "They have a lot of these mom-and-pop zoos down here," Barry says.

About Trevor? "He really became more of a character than I planned," Barry says, chuckling. "I just got to like him a lot. He's a lonely, romantic orangutan. That's a dilemma for you right there."

  Insane City comes to tell us that South Florida truly is insane - much like the country itself, much like author Dave Barry.

Not Trevor. He's a hero. He's no looker, but he has his points.