Egyptian pharaoh Kahmunrah (Hank Azaria) says it best upon meeting Darth Vader. "There's just too much going on here," he quips, referring to the heavy breathing, the operatic black cape and the villainous vibe.

The same could be said of "Night at the Museum: Battle of the Smithsonian," the sequel to the 2006 comedy starring Ben Stiller as a night watchman who discovers the Museum of Natural History in New York comes alive -- literally -- after dark.

The follow-up largely shifts to the Smithsonian Institution in Washington, D.C., and has historical figures, fictional characters, animals, paintings, statuary, action, noise and stunts to spare. It's as overstuffed as a suitcase about to burst its zipper, which might be appropriate since the movie doubles as a vicarious vacation to the nation's capital.

As "Night at the Museum" opens, Stiller's Larry Daley is still in Manhattan but he's a successful infomercial king who peddles his inventions on TV. He's on the brink of meeting with Wal-Mart when he learns that the natural history landmark is shipping its old-school exhibits (and his friends) to storage at the Smithsonian.

He hotfoots it to Washington, D.C., and disguises himself as a security guard to find the ancient, golden and magical tablet that will allow the denizens of the subterranean archives or the mainstream exhibits to come alive.

In addition to reuniting with his old pals, Larry comes face to face with the power-mad Kahmun-rah along with Ivan the Terrible (Christopher Guest), Napoleon Bonaparte (Alain Chabat), Al Capone (Jon Bernthal) and Amelia Earhart (Amy Adams). If the Egyptian ruler succeeds in freeing his Army of the Underworld, he can take over the museum and expand his empire from there.

It's up to Larry and the aviation pioneer, bursting with spunk and the crisp banter of Katharine Hepburn in her heyday, to make all right with the world and the underworld.

"Night," directed by Shawn Levy who also did the first film, manages to make history come alive as characters step into V-J Day merriment in Times Square or visit the Lincoln Memorial where the president's statue talks, moves and dispenses romance advice.

But for every reference to the Tuskegee Airmen or painter Edward Hopper, there are capuchin monkeys slapping Stiller in the face. Plus, "The Thinker" by Rodin clearly isn't pondering the suspicious and obvious lack of guards, security cameras, traffic or that pesky Homeland Security department.

Screenwriters Thomas Lennon and Robert Ben Garant try to accommodate the popular characters from the original film as they pile on the new ones, threatening to collapse their comedic and adventurous house of cards. The movie is at its best when Larry and Amelia venture into the Air and Space Museum and at its worst when a miniature man riding a squirrel joins the already frantic fray.

"Night" plays a bit like an infomercial for the sprawling Smithsonian and for D.C. as a tourist destination but it also uses a key mathematical constant as a clue. It's like a chocolate cake with zucchini as a secret ingredient; the kids won't even know it's good for them.