A couple of aliens come to earth disguised as a Cowboy and Cowgirl calling themselves Mr. and Mrs. Zimm buy a pet shop from its owner in an attempt to try to abduct some of earth's children to sell as pets to other alien races. Meanwhile, young Dena Yeagher and her family have just moved into town. Her family is in the witness protection program do to her father discovering some unpleasent facts about his employer.
So Dena goes to the pet shop to find a dog. She meets Mike, a nice kid who badly wants a pet turtle. Along with his friends Nicky and Alexis. One by one all four kids are given one random pet free of charge. The pets at first seem normal, until they change into their true alien forms. The kids meet when they return to the pet shop because their pets stop eating and seem to need some type of "vitamins" to keep them healthy that the two aliens feed them.
film provides examples of:
- Adult Fear: The film doesn't shy away from placing appropriate emphasis on the parental fear of one's child being kidnapped when Mr. Yeagher finds Dena's baseball and starts demanding that Mrs. Zimm give him answers.
- A Form You Are Comfortable With: The pet's in their natural form are an odd, though adorable assortment of entities. However, with their "appearance changing" ability, they are able to change their form to appear as normal earth animals.
- Alien Abduction: Mr. and Mrs. Zimm attempt it with the children, they fail to get the kids but manage to take Curly and Babe instead.
- All Alien Animals Are Dogs: At least one of the alien pets is very dog-like. He even turns into a puppy for camofluge.
- Asshole Victim: The pair of mob enforcers Curly and Babe sent to exterminate the Yeagher family are eventually abducted by the evil aliens.
- Attention Deficit... Ooh, Shiny!: The pet aliens are very easily distracted.
- The Bad Guy Wins: The children are saved but Mr. and Mrs. Zimm get away with kidnapping two humans.
- Big Eater: The pet aliens.
- Butt-Monkey: Curly and Babe.
- Bizarre Alien Biology: Mr. and Mrs. Zimm appear to be normal humans until the take their hats off.
- Harmless Villain: Curly and Babe.
- Hidden in Plain Sight
- Human Aliens: Mr. and Mrs. Zimm.
- Innocent Aliens: The pet aliens.
- Misfit Mobilization Moment: After the kids are first told they are to become pets themselves they attempt to make a run for it.
- Police Are Useless: Marshall Dave, the Yeagher family's bodyguard never once pulls out a side-arm. The man doesn't even try to break down the one door standing between himself and one of his charges. He just stands idly by as the mother and father try break it down.
- Ridiculously Cute Critter: All four pet aliens.
- Starfish Language: Mr. and Mrs. Zimm's native language.
- Starring Special Effects: The pets in their alien forms.
- Sufficiently Advanced Alien: The unidentifed alien race of Mr. and Mrs. Zimm has perfected the ability to travel anywhere any time they wish through the use of a transporter device.
- Took a Level in Badass: The pets manage to rise to the challange when their human friends are in danger.