Seventeen murders brought Agent Jessica Langlow back to Europa.

Europa was her least favorite colony in the solar system. The moon's mining workforce had been infused with criminals and indebted poor. Its Upper and Underground City was a corrupt and greedy institution that allowed all kinds of vices like gambling, prostitution, drugs and alcohol. But Europa has something more unique than its supplies of water, mercury and silver; five hundred meters of ice cover a vast ocean of animals.

Jessica had investigated the Upper City before, removing a corrupt entity known as the Circle. But there are old members still about the city complex, which adds another twist to the crimes. They appear to be involved with the permission of Earth.

The Council oversees the operation but there is no love between them and the workers. The murders of the poor don't bother the Council but the loss of the CATR controls over the cargo shipments draws concern.

As she investigates the murders, she learns that Europa had changed. The Droners and Ropers are even more isolated from each other. Security officers were individually tending to their duties without coordination with each other. The indebted workers were prospering and yet output was increasing. And a casino had been built and thriving.

But Agent Langlow quickly discovered that she wasn't the first person sent to Europa. Special operatives were sent to secure cargo labeled as "future weapons." Another sinister plot has shaken Europa's mystery and too many secrets obstruct her ability to carry out her mission.