Kingsman: The Secret Service" makes up its own rules as it goes along. It asks to be taken seriously, then turns ridiculous, then brings out the horn section to indicate the hope for triumph of good, then shows people’s heads exploding in a CGI sequence intended to be funny. It tries to get by on charm, and like a lot of movies, and people, who make that attempt, "Kingsman" does have charm — just not enough.

It tells a story involving a society of secret agents that operates out of a high-end London tailor shop, and even though the movie opens in 1997, Colin Firth does not once appear in the baggy trousers of that era. From the beginning, he wears the more form-fitting, skinny-legged pants common to today, probably because Firth knows he looks good in them. Let’s just say it: That man can wear a suit.

A riff on British spy movies, it stars Firth as Harry, who is asked by his leader — Michael Caine, of course — to find a potential recruit to replenish their ranks. Harry decides on the son of the man who saved his life years before. Eggsy (Taron Egerton) is a working-class kid with no prospects and nothing to lose. The movie’s depiction of working-class despair is committed. It’s about the only thing that director Matthew Vaughn doesn’t regard as funny.

"Kingsman" shows characters discussing spy movies and deciding what about their present circumstances is and isn’t like a James Bond picture. At the same time, Vaughn hits most of the familiar stations of a Bond movie, including the introduction of gadgets in the first hour that get used in the second. Vaughn co-wrote and directed "Kick-Ass," and perhaps the looseness and outrageousness of that earlier film — the way it satisfied genre conventions, even while satirizing them — is what Vaughn was trying to do here.

But this is the first time that Vaughn ("Layer Cake," "Star Dust") has lost control of his story. Long before it ends, the movie has already started to feel like a long stunt, a genre parody for the sake of itself, with no larger comment or insight to offer. Samuel Jackson shows up as a criminal mastermind, a technology mogul who schemes to kill a billion people, but is too delicate to witness the violence he re- creates. Jackson plays him with an exaggerated lisp that goes in and out, in a performance that’s too silly for the movie’s more serious sections involving actual murder.

Though at first Harry and the new recruit’s burgeoning father-son relationship seems to be at the core, there really is nothing in "Kingsman" to ground it in anything like real emotion. It tries to hold us through scale and outlandishness, and yet every time the script springs a surprise on us, it’s always for the worse.

But here’s the real irony. The attempt may have been to do a postmodern, ironic, 21st-century spin on Bond. Yet it most resembles the old TV show "Get Smart," which was conceived as a Bond satire in the mid-1960s. As with "Get Smart," the mix of comedy and corpses in "Kingsman" becomes callous and clueless — in addition to seeming about 50 years behind the times.

In the end, the most interesting thing about "Kingsman" might be that it’s the second movie to come out in a week (the other, "Jupiter Ascending") to identify computer technology and the technological ruling class as the ultimate threats to peace and happiness. Sometimes movies contain truths that their filmmakers are unaware of, just like dreams often mean more than dreamers realize. This may be a trend worth watching.

Review by Mick LaSalle, San Francisco Chronicle