Ronald Donald Almondotter, the protagonist and narrator, accepts an internship under his maternal grandfather, Seumas Finneganstein.

He accompanies both men from America to Tanzania, in search of an intelligent earthworm documented by gemstone-collector Gordon Whillikers.

At the advice of general-store owner Baba Pambazuka, they intuitively pursue the intelligent earthworm's habitat in the extinct volcano Kukumlima, without set directions.

Finding Kukumlima accidentally, they discover Gordon Whillikers, who is held captive by the now-gigantic earthworms, and required to annually collect the tiny elephant mice used by the worms for unknown purposes.

The Worms of Kukumlima is no longer in print in its original form; but is included in Pinkwater's compilation 4 Fantastic Novels.