WHAT WOULD a 1950s science-fiction B-movie be like if you inverted the plot and put it in CG? It'd be Planet 51, where humans invade another planet, aliens wear cardigans, and Dwayne "The Rock" Johnson is white.

The algae-green residents of Glipfog are living a traditional, suburban, Happy Days life—until astronaut Chuck Baker (voiced by the Rock) touches down and finds, to his surprise, an English-speaking society that includes unlikely teenage hero Lem (Justin Long), his crush Neera (Jessica Biel), and nerdy buddy Skiff (Seann William Scott). But Glipfog's noseless aliens are certain that Chuck wants to both eat them and reprogram their brains, which inspires a witch hunt for the human astronaut and (surprise!) some morals about xenophobia.

Perhaps because you can't see the Rock's bulging biceps or hear his booming baritone (his voice sounds a bit higher than normal), the usually entertaining wrestler-turned-actor neither ruins nor steals the show. This is the first film from Spanish animation studio Ilion, and while they've figured out how to insert "adult" tidbits into kiddie fare, they haven't figured out how to deliver either the loveable oddball characters or the rollicking story that'd make the movie work. I'll raise an eyebrow—just one—to that.