It has been thirty years since the end of the brutal Andromeda War. The Andromeda Republic was barely able to defeat the Zeta Empire, and its remnants retreated into uncharted space. At first, peace has been settled across the galaxy, but over the decades, the Andromeda Republic became more and more paranoid of the Zeta Empire returning. As a result, they slowly became tyrannical and started to use terrorist tactics to maintain control across the Andromeda Galaxy. But little did they know, the Zeta Empire has secretly been preparing and growing stronger to invade the Andromeda Republic ever since their defeat. With the republic going into turmoil, it is now the perfect opportunity for the Zeta Empire to strike.

After the Zeta Empire returned from uncharted space on a full-scale assault against the galaxy, the Great Zeta War has started. Two years later, both factions were at a bitter stalemate. But the Andromeda Republic decided to hire a pair of former bounty hunters; a skilled sniper and pilot Bryce Kiness, and Agnar Reise, a heavy weapons specialist, to sneak behind enemy lines to find a way to end the war. Meanwhile, one of Zeta Empire's flamethrower specialists, Kyle Savo, goes rogue and befriends a teenage prisoner of the empire named Arrua Veronis. After making a daring escape from the Zeta Empire, they come across the two mercenaries and decide to join forces, becoming the galaxy's most daring group of mercenaries, the Marauders!