PSR centers on events during the eve of mankind's first interstellar explorations. The location is Mars with a new spaceship, the PSR, running transportation routes from mining colonies on Mars to Earth. PSR is an acronym for probe, survey and reconnaissance. Four starships under construction in Martian orbit are almost complete. Each will carry three PSRs to survey G-type star solar systems within 50 light-years of Earth. However, a rogue alien faction, unknown to the colonists, wants to destroy the colonies and use Mars for their purposes. Tension between Mars and Earth is already high due to a recent Martian independence declaration and their right to succeed upheld by international court. A small segment of Earth officials have bought into the rogue aliens' plan, intent on revenge and alien technology profiteering. One woman stands in their way, but not before the first space battle between humans and aliens begins.