A scientific expedition into the Central Australian Desert leads two boys, two professors and their guide into a curious set of circumstances that hinges on their discovery of a strange species harking back to prehistoric days. The species is a kind of ant man. They walk upright, have an intelligence that makes itself understood by telepathy and live in a rather highly developed society underground. But there are dangers. The professors' and the boys' first experience with the streams of formic acid shot out by the creatures is a dangerous warning. But developments progress to reveal a dissension within the ant society and the humans help a liberal faction win out against their oppressors before they return, breathlessly, to their own world. A well worked fantasy in which suspense and logical scientific conclusions create a sense of reality.