Born is a member of the primitive human society that has lived peacefully on Midworld for hundreds of years, careful not to disturb the natural balance of the jungle.

The world is disrupted by the arrival of an exploitative business venture from Earth whose representatives know nothing of the delicate stability of the planet.

Born realizes that the newcomers are on his world to gain a life-extending drug from the burls formed by the They-Who-Keep trees around buried people.

Losting's brain and mind are absorbed to form part of a developing planet-wide network of consciousness involving They-Who-Keep and the furcots.

Spider Robinson praised Midworld as an adventure novel, citing it for "an intriguing premise [and] a richly inventive background world," but noted that the writing "is just a cut or two above slushpile level.