From one movie to the next, nobody remembers exactly who is inthe Expendables. A clearinghouse for aging tough guys — at various timesBruce Willis,Jet Li,Jean-Claude Van Damme,Arnold SchwarzeneggerandMickey Rourkehave made appearances — the franchise seemed to have run its course by the bloated “The Expendables 3” (2014).

But the latest chapter, “Expend4bles,” makes the best case possible for resurrecting this moribund franchise. The story is good, the script devises some genuinely gripping situations, and there are some laughs to lighten the mood. Sylvester Stallone and Jason Statham have a winning rapport, and the movie doesn’t overstay its welcome. Unlike “The Expendables 3,” “Expend4bles” gets in and out in a trim 103 minutes — or more like 95, if you don’t count the credits.

For those who need reminding, the Expendables are a band of jolly mercenaries that intelligence agencies turn to when they need a nasty job done in secret. In that way, they’re kind of like the race-car enthusiasts in the“Fast & Furious” movies, only slightly less silly.

The team is led by Barney (Stallone) and his right-hand man, Lee (Statham), who insult each other constantly because they love each other so much. Perhaps it’s because they’re so into each other that they don’t notice that their team keeps changing personnel from movie to movie. A mildly funny aspect of the franchise is that new members are usually presented as if they’ve always been there. So this time, rapper Curtis “50 Cent” Jackson is in the crew, and so are Megan Fox (“Transformers”) and Levy Tran (from TV’s “MacGyver”), while Andy Garcia is Marsh, their CIA contact.

The movie opens with a jolt, a sudden attack on a chemical plant once owned by Libyan dictator Moammar Gadhafi. International bandits obliterate the place in a matter of minutes, and the spectacle is disturbing, albeit in an entertaining sort of way.

The villains are in search of nuclear detonators — uh-oh, that can’t be good — which leads the CIA honcho, Marsh, to bring in the Expendables. Their assignment is to prevent the detonators from falling into the hands of the evil Suarto (Iko Uwais). Or, if they can’t do that, they have to at least stop him from putting those detonators to use.

这样的话,“Expend4bles”是完全的故事like that of a half-dozen recent superhero movies, in which the universe (or multiverse) will be destroyed if the monomaniacal villain takes possession of the all-powerful gems or stones or pieces of magic statuary. All the same, at least “Expend4bles” literalizes the metaphor, which is and always has been about nuclear war.

Besides the movie’s banter, its characters, its pacing and its action sequences, everything in “Expend4bles” is ridiculous. But all that other stuffcanbe ridiculous, and it doesn’t much matter. For example, the bad guys’ brilliant plan is to detonate a nuclear device in Russian waters, so as to provoke World War III between the United States and Russia. Why? Because they think that World War III will be good for business. What’s their business? Smelting? Geiger counter sales? It’s utterly absurd.

Then again, who cares, as long as the movie gets all the fun stuff right, such as Galan, the youngest member of the Expendables. Galan is the son of the character played by Antonio Banderas in “The Expendables 3,” and Jacob Scipio plays him by flat-out imitating Banderas at his most intense. The movie doesn’t overplay it, just giving Galan enough lines that every time he says something, it’s hilarious.

It took the franchise four tries, but with “Expend4bles,” they’ve finally made a solid and consistently effective action movie.

Reach Mick LaSalle: mlasalle@sfchronicle.com