The miner Endre Burton has left a trail of blood throughout the underground city of Base One – most of it his own – before expiring ingloriously on a deserted street. The list of suspects has only grown in the interval since his death, adding the three miners who accompanied Burton on his final night, plus a devious trader of precious metals, and gangster Paget Reid’s personal aide.

The Base One police have made their choice, arresting Guard cadet Dorrin Kappler for Burton’s murder. Dorrin proclaims his innocence, and enlists his classmate Alejandro Detweiler to help in his defense.

At first, the case seems hopeless. Dorrin followed Burton down a darkened passage, and lied about it later on an official report. Worst of all, he has Burton’s blood on his clothing. To save their friend, Al and his girl Abrianna need a different explanation. Questions posed to the miners are met with evasion and scorn, followed by an attempt to lose Al in the labyrinth of mines that run beneath Base One. Once free of the mines, Al finds that he is in trouble at the Guard Academy as well. Drop the case, or face expulsion, he is told. Not only is Dorrin’s future in jeopardy, so is his.

Dorrin’s trial begins, and time runs short. Al must find an elusive witness, and confront Abrianna as she takes the stand. Finally, the verdict is read, but Al is not satisfied with the result. He convenes a second trial, to be held at the crime scene, and summons all participants to attend. Together, they will learn who killed Endre Burton.

Successful at last, Al graduates from the Academy and accepts his commission. Shortly after, he receives his first mission.

This time, it’s a missing person.