Nigel Shirazi was first in line for the chairmanship of Asbaran Solutions, one of the prominent "Four Horsemen" mercenary companies. First in line...until his drinking and temper caused him to fail out of college and get disinherited by the family. Now he leads the life of a playboy, enjoying a stipend from the family to stay out of the way. But someone is out to get his family, and Nigel is all that stands between the hidden enemy and the destruction of Asbaran Solutions and the Shirazi family.

The slaughter is on! Across the galaxy, human mercenaries are being ambushed, and an ever-increasing number of companies aren't returning from their contracts. Someone even appears to be plotting the demise of the premier Four Horsemen companies, and disaster for the other three companies has only been averted by the narrowest of margins. Sansar Enkh, the president of The Golden Horde, knows her company is likely to be next, but has no idea who is behind the attacks, or when they will strike her beloved Horde.

Peacemakers. The Galactic Union's most capable enforcers and resolute negotiators, their name alone elicits fear and awe among the Union's citizenry. Having completed a harrowing confirmation mission, Jessica Francis stands ready to become Earth's first Peacemaker and believes obtaining her commission is a mere formality. However, certain members of the Guild question her ability. Worried that she'll fall back on her mercenary ways, they want Jessica to prove her mettle.

For more than a century, Winged Hussars has been the richest of Earth's mercenary companies, as well as the only one to specialize in space warfare. Led by Alexis Cromwell, they have carved out a reputation in the galaxy for being dependable, unflappable, and lethally efficient. Until people began shooting at them everywhere they went.

It's the 22nd century. Humanity has taken its first steps into the galaxy, and we've found ourselves in a vast playground of alien races and cultures. As the newest players on the universal stage, though, we're at the bottom of the food chain. Welcome back to the Four Horsemen universe, where only a willingness to fight and die for money separates humans from the majority of the other races. While some of the stories deal with mercenaries, others introduce listeners to the other guilds, organizations, and races that make up the landscape of the Four Horsemen universe.

The plot by the Galactic Union’s Mercenary Guild against the Four Horsemen has culminated in an invasion of Earth. Faced with an overwhelming force, the human mercs had no choice. They’ve fled, leaving Sansar Enkh to go to the Mercenary Guild headquarters on Capital Planet to stand trial for humanity. On the run, Jim Cartwright and Nigel Shirazi have travelled to the Winged Hussars’ secret base of New Warsaw, in an effort to convince Alexis Cromwell to join the fight, while the other mercenaries who escaped the fall of Earth have gone to the perceived safe haven of Karma.

Two hundred years ago, aliens invaded Earth. A violent war followed. The enemy won. Some of us escaped, most of us didn’t. On Proxima they flourished - the invasion forgotten. On Earth we floundered - the horror began. Their world is advanced, peaceful, and secure. Our world is broken, savage, and overrun. A new invasion is coming. A hunger that has swallowed half the universe. They don’t care which planet we live on. They want to end us all. But where there is life, there is hope. And where there is hope, there are heroes. This time, vengeance will be ours.

War has come to the worlds of Humans. The rich planet of Tau-Rietzke, however, is far from Earth and the Mercenary Guild’s invasion, and its alien-registered mercenary companies are a safe haven for humans on the run. Organizations like the Midnight Sun Free Company. Having just completed another successful mission and taken possession of three Raknars, it was party time for Saisho Branco and the Midnight Sun personnel, and they were enjoying a little down time...until the war spilled over into their corner of the galaxy and two competing organizations showed up to steal the Raknars.

The Omega War is in full swing. Earth has fallen to General Peepo’s army, and the surviving human mercenaries have taken refuge at the hidden Winged Hussars’ base in New Warsaw. On Earth, the defensive forces fight to keep the hearts and minds of their fellow humans, but Peepo’s plans are slowly converting the people to her way of thinking, and the Mercenary Guild troops continue to root out the forces arrayed against them.

While the occupation of Earth continues, MinSha mercenaries under the command of Major General Drehnayl have assaulted human-held colonies in the outer rim, wiping them out. With the famed Four Horsemen nowhere to be found, the Mercenary Guild’s attempt to instill fear and subvert humanity is perilously close to reality. Tasked with finding the MinSha is Jessica Francis, Earth’s first Peacemaker, but the odds aren’t in her favor. Jessica realizes that finding Drehnayl's forces isn’t enough - she must do something to stop their atrocities and end their reign of terror.