In the novel, renegade biotechnologist Vergil Ulam creates simple biological computers based on his own lymphocytes. Faced with orders from his nervous employer to destroy his work, he injects them into his own body, intending to smuggle the "noocytes" (as he calls them) out of the company and work on them elsewhere. Inside Ulam's body, the noocytes multiply and evolve rapidly, altering their own genetic material and quickly becoming self-aware.