Tired of weathering constant attacks on their colony, ants shrink a destructive boy, named Lucas (Zach Tyler Eisen), to their size and sentence him to live among them until he learns the errors of his ways. Guided by his insect guardians (Julia Roberts, Regina King, Bruce Campbell), Lucas discovers a world he never knew existed and soon joins forces with his new friends to combat an exterminator (Paul Giamatti) who threatens their colony.