In view of the fact that the hunt in this sequel to 2004’s “National Treasure” involves significant landmarks like the Statute of Liberty and Mount Rushmore, it may be rather appropriate that “Book of Secrets” should be monumentally silly. Indeed, from any logical point of view, this is one of the goofiest pictures in a long while. But it’s also well-made, and, under the busy direction of Jon Turteltaub, actually moves better than its predecessor after a talky and tedious opening half-hour’s exposition (coming in about ten minutes shorter, a virtue that allows a lessening in the number of climaxes the first one had). So viewers looking for the dumbest sort of escapism are likely to be satisfied, just as kids used to be when they flocked every Saturday morning to those idiotic serials.

But like the first picture, this one doesn’t add the panache and wit to the cliffhanger template that “Raiders of the Lost Ark” did. And the plot is, if possible, even more preposterous than last time. If you’ll remember, the original had our heroes (and heroine) chasing down a vast horde of goodies collected over the centuries by secret societies and eventually hidden away by our Founding Fathers. This one deals with nothing less that the famed Cibola, the lost city of gold whose mythic origin goes back to medieval Spain but was later connected to Spanish exploration in the New World. It also has something to do with the assassination of Lincoln and, I think, a Confederate plot to resume the Civil War by acquiring a new source of funding to resume the fight—though that part of things is even more obscure than most of the plot.

But the impetus for treasure hunter Ben Gates (Nicholas Cage) and his father Patrick (Jon Voight) to take up the chase is the revelation by a sinister fellow named Mitch Wilkinson (Ed Harris) of a lost page from the diary of John Wilkes Boothe that suggests that their ancestor Thomas was the mastermind behind the Lincoln’s murder, and their desire to clear his name. The search involves a cipher, numerous puzzles, a pre-Colombian language and secret messages in important places, as well as (of course) a desperate and destructive car chase and (less predictably) the titular book—a legendary volume compiled over the decades for the eyes of the president alone and containing information on all the biggest mysteries of history. And it takes Ben, Patrick, Ben’s mother Emily (Helen Mirren), his ex-girlfriend Abigail (Diane Kruger) and his comic-relief partner and resident electronics expert Riley Poole (Justin Bartha) in various combinations to Paris, Windsor Castle, the White House, Mount Vernon, the Library of Congress and Mount Rushmore. But the speed of the itinerary causes less of a blur than the labyrinthine connections among the clues and revelations, which are rushed over with an alacrity that suggests that the filmmakers were all too aware that the story is the sheerest nonsense that couldn’t bear the slightest scrutiny. So they just push on headlong, creating a movie that’s like a cinematic rollercoaster riding roughshod over plot holes and implausibilities fast enough that no one will have time to notice them—or care much about them if they do, even if on reflection even the dimmest observer will wonder what purpose any of those nineteenth-century Machiavellians could possibly have had in setting up so elaborate a puzzle in the first place, or why Calvin Coolidge, of all people, would have gone to such ridiculous ends to keep it secret.

Amidst all the mindless action the effort to add some humanity to the hubbub by creating friction between Ben and Abigail on the one hand and Patrick and Emily on the other comes off as laughable. (And what Mirren is doing in stuff like this—besides earning a hefty paycheck, of course—is beyond comprehension. As far as Cage and Voight are concerned, well, after “Ghost Rider” and “Anaconda,” they obviously have no shame.) And the patriotic claptrap associated with the president (Bruce Greenwood, looking bemused—as well any Canadian might in the part) is laid on so thick one half expects a chorus of Marines to start piping away “The Battle Hymn of the Republic” in the background.

The rest of the supporting cast fare no better. Harris was apparently paid by the glower as Wilkinson, a villain who boringly turns out to have a noble streak despite his initially homicidal bent; Kruger is shrill, Bartha merely repeats the nerdy shtick he worked to death the first time around, and Harvey Keitel saunters through the repeat role of FBI agent Sadusky without breaking a sweat—an easy payday indeed.

Visually “Book of Secrets” is just okay—cinematographers John Schwartzman and Amir Mokri can’t hold a candle to the original’s Caleb Deschanel, and by current standards the effects in the final reel are pretty anemic, more chintzy amusement park quality than top-of-the-line Bruckheimer. Once again Trevor Rabin contributes a brassy but basically generic score.

There’s one great Hollywood movie that ends with its stars in peril on Mount Rushmore, and this isn’t it. The volume out to have a yellow-and-black cover, because it’s really “North by Northwest” for dummies. But undemanding viewers made “National Treasure” a hit, and they’re likely to do the same for “Book of Secrets,” meaning a third go-around is almost inevitable. But it will be hard to outdo this installment for narrative imbecility.