Nineteen-year-old Matthew Lionheart finds himself accidentally propelled from modern day New England to the year 2499 by a time machine, which he loses shortly after his arrival. He teams up with a teenage Martian girl, Mia Omega, in hopes of retrieving the machine. As his friendship to Mia grows, he begins to see that she is more than just a common street vagrant. Everything in this dystopian future hinges around a small, iced-over moon of Jupiter, the "Pearl of the Outworlds"-Europa-where below the icy crust is an ocean of fresh water. Due to the overpopulation of Earth, fresh water has become the most sought-after resource in the galaxy. Earth's fascist, governing body barricades Europa and demands an unconditional surrender from the cybernetic Jupitorians. While Lionheart's true goal is to retrieve his lost time machine and get home, his relationship with Mia entwines him in an interplanetary power struggle over Europa.