During an interstellar war one side develops a language, Babel-17, that can be used as a weapon. Learning it turns one into an unwilling traitor as it alters perception and thought. The change is made more dangerous by the language's seductive enhancement of other abilities. This is discovered by the beautiful starship captain, linguist, poet, and telepath Rydra Wong. She is recruited by her government to discover how the enemy are infiltrating and sabotaging strategic sites. Initially Babel-17 is thought to be a code used by enemy agents. Rydra Wong realizes it is a language, and finds herself becoming a traitor as she learns it. She is rescued by her dedicated crew, figures out the danger, and neutralizes its effects.