In the year 1960, protagonist 10-year-old Arthur lives with his grandmother Daisy in a quiet farm house on a dirt road, in a small rural community in Northeastern Connecticut (based on Sterling, Connecticut). His grandfather Archibald has recently gone missing and he sees little of his parents (who are away looking for work). Daisy entertains Arthur with stories of his grandfather's adventures in Africa, featuring the tall Bogo Matassalai and the minuscule Minimoys, of whom the latter now live in Archibald's garden, protecting a collection of rubies. Arthur becomes enamoured of a picture of Selenia, the princess of the Minimoys. When Daisy receives a two-day deadline to pay a large sum of money to a building developer named Ernest Davido, who plans to evict the two, Arthur looks for the rubies to pay off the debt and discovers various clues left by his grandfather. He is met in the garden by the Bogo Matassalai, who reduce Arthur to Minimoy size. From the Minimoys, Arthur learns that they are in danger from Maltazard, a Minimoy war hero who now rules the nearby 'Necropolis', after corruption by a weevil, by whom he has a son named Darkos.