 Shortly after returning to Seattle, teenager Mike Jones has a telepathic conversation with Mica, the alien princess he rescued at the end of Startropics, until the message is suddenly cut off. Not thinking much of it, he visits his uncle, who is examining an odd text he discovered on his recent archeological expedition. Mike manages to crack the code, but as a result is unexpectedly hurled through time. When he comes to, he finds himself in the stone age. After finding an odd block known as a Tetrad, he is thrown forward in time to Egypt during the reign of Cleopatra. Soon, he realizes that the text is leading him on a quest to locate all of the Tetrads, and also discovers that Zoda, the alien he defeated to save his uncle and Mica, has returned and wants the Tetrads for himself. After crossing time, Mike eventually returns to C-Island of the present and finds that all of its residents have been turned into boars. Racing through the cave that marked the beginning of his first adventure, Mike defeats Zoda once more, frees Mica and restores the forms of the islanders. In gratitude, the chief of the islanders helps assemble the Tetrads, releasing Mica s father, Hirocon, who used the Tetrads as a method to escape Zoda s forces when he fled their attack on their homeworld, Argonia. After thanking Mike for all of his hard work, Hirocon and Mica use their psychic powers to return to Argonia and begin rebuilding the civilization that Zoda destroyed.