LOS ANGELES: “Ender's Game,” Harrison Ford's science fiction return to the big screen, easily topped the North American Box Office on its debut weekend, according to preliminary figures released Sunday.

The film, which depicts a battle to save the human race from alien attack, took $28 million in theaters, industry tracker Exhibitor Relations said, knocking wacky Jackass comedy “Bad Grandpa,” ($20.5 million) into second place.

“Last Vegas,” starring Michael Douglas, Robert De Niro, Morgan Freeman and Kevin Kline, on a bachelor party in Sin City, entered in third spot, taking $16.5 million, with animated comedy “Free Birds,” ($16.2 million) in fourth.

“Gravity” — with Oscar winners Sandra Bullock and George Clooney as astronauts adrift in space after a devastating accident — scored $13.1 million in fifth spot, taking its gross takings to $219 million since its release.

“Captain Phillips,” based on a true story and starring Tom Hanks as a cargo ship captain captured by Somali pirates, earned $8.5 million.

Steve McQueen's “12 years a Slave” earned $4.6 million between Friday and Sunday, jumping from last week's eighth place to seventh, edging out “Cloudy With A Chance of Meatballs 2,” which took $4.2 million.

The reprise of “Carrie,” the latest film adaptation of the Stephen King horror tale about an outcast schoolgirl out for revenge, earned $3.4 million, falling to ninth from last week's sixth place.

“The Counselor” with Michael Fassbender, Penelope Cruz, Cameron Diaz, Javier Bardem and Brad Pitt, earned $3.25 million but fell from fourth place to round out the top 10 on its second week in theaters.