“Think Like a Man Too” sticks to the romantic comedy formula.

The sequel to 2012’s “Think Like a Man” features the standard overstuffed ensemble cast. It mixes chaotic comedy with soap-opera melodrama. There’s the killjoy character, too.

And there’s the crazy, funny guy. Actor-comedian Kevin Hart plays that part again in “Think Like a Man Too,” as he previously did in “About Last Night” and the first “Think Like a Man” movie. The latter three films also feature Michael Ealy as a character who’s as earnest as Hart is crazy.

“Think Like a Man Too” reunites the couples from the original film in Las Vegas for a special occasion. Michael (Terrence J) and Candace (Regina Hall) are getting married at Caesars Palace. The wedding will not go off without a hitch. Make that several hitches.

Subplots include the quest by Jeremy (Jerry Ferrara) and Kristen (Gabrielle Union) to conceive a child; career choices that threaten the relationship between Lauren (Taraji P. Henson) and Dominic (Ealy); and unpleasant blasts from the past for Zeke (Romany Malco) and Mya (Meagan Good).

Hart returns in “Think Like a Man Too” as trouble-maker Cedric. The comic actor also narrates the film through occasional voiceovers.

Hart sets the story up as a competition between the men and the women. The respective mission for the bachelor party team and bachelorette party team is to outdo each other in the amount of fun each team has on the eve of Michael and Candace’s wedding.

That fun includes the ladies going old school when they visit a club and romp through a music video-style sequence featuring Bell Biv Devoe’s 1990 hit “Poison.” The misplaced nostalgia stops the movie’s plot cold.

The comedy in “Think Like a Man Too” parallels the many Vegas comedies that preceded it: 2008’s “What Happens in Vegas,” 1997’s “Vegas Vacation,” 1992’s “Honeymoon in Vegas” and, of course, 2009’s “The Hangover.” Stuff happens.

The cast throws itself into the party. And it is amusing, for instance, when Hart’s Cedric and his pals play dress up for the higher purpose of getting Cedric out of a financial misunderstanding.

In addition to the physical free-for-all that is the movie’s comic zenith, Cedric gets some good lines. Disillusioned by his friends’ unwillingness to party big time in legendary party town Las Vegas, the disgusted Cedric says tells them, “I’m sick of this non-tourage!”

After the film peaks, “Think Like a Man Too” downshifts into deep melodrama. It becomes a different movie. But then the whiplash effect is part of the formula.

The script’s belabored third-act machinations effectively kill whatever laughs might sneak out of the misery. And once the fun is over, the screenwriters collect the loose ends and tie them into unforgivably forced outcomes.