During a deep-space expedition, Nova and Luna intercepted a series of mysterious transmissions encoded by mathematical function rules. They organized the received input-output pairs and tested several possible functions against the data. Some relationships explained only a few signals, while others failed when applied to new transmissions. By verifying each candidate with additional inputs and rejecting inconsistent patterns, they identified the single function that matched every message. Using the correct decoding rule, they translated the alien transmissions and successfully established communication with the distant civilization.