There's something charming about Tim Johnson's alien-invasion animated film, much of it due to the voicework of Jim Parsons (The Big Bang Theory) as an alien. Good thing, because its themes — be courageous, don't judge a book by its cover, friends are important — are pretty familiar. The story concerns a race of intelligent but cowardly aliens, known as the Boov, who have spent their lives running from their mortal enemies, the Gorg, and are seeking shelter on Earth. Led by Captain Smek (voiced by Steve Martin), the Boov initiate a polite takeover — sucking humans into vacuum tubes and relocating them to a new, pre-fab community in the Australian Outback, complete with tiny houses, picket fences and an amusement park. But one human, Tip (voiced by Rihanna), is left behind and must work with Oh (Parsons) to find her mother. The jokes and visual hi-jinks are typical of the genre, but Parsons playing off a capable Rihanna makes this film worth the time. In 3-D, in select theaters. Starts Fri., March 27.