The world's richest man, Magnus McAloon, has tragically died in a rocket experiment gone wrong. The sole heirs to his estate are his four beloved pet guinea pigs: Hot Head, Lunk, G-Chip and Big Pig (who is actually a capybara, but don't tell him that). Not everyone is happy - especially the members of the McAloon family, who are determined to get back the fortune that they feel belongs to them, and not the newly mega rich guinea pigs.