Mladi Artur živi sam z babico in najraje posluša zgodbe o podzemnem kraljestvu malih bitij, ki skrivajo neprecenljiv zaklad.Ko Artur izve, da ju namerava neusmiljeni nepremičninski agent izseliti, se odloči poiskati zaklad. S pomočjo čarovnije, ki ga pomanjša, najde vhod v deželo Minimojčkov. Tam spozna lepo princeso in skupaj se odpravita na veliko pustolovščino, polno neverjetnih dogodivščin, grdih zlobnežev in prevar, toda prav najmanjšim junakom ponavadi uspejo največje zmage.
Arthur is a spirited ten-year old whose parents are away looking for work, whose eccentric grandfather has been missing for several years, and who lives with his grandmother in a country house that, in two days, will be repossessed, torn down, and turned into a block of flats unless Arthur's grandfather returns to sign some papers and pay off the family debt. Arthur discovers that the key to success lies in his own descent into the land of the Minimoys, creatures no larger than a tooth, whom his grandfather helped relocate to their garden. Somewhere among them is hidden a pile of rubies, too. Can Arthur be of stout heart and save the day? Romance beckons as well, and a villain lurks.