The game blends together two most popular genres – action and role-playing. Story of 4th Battalion transfers us to the far future, when mankind has colonized the entire Solar system. But war is always there if humans are involved. Crisis of power between Earth's colonies which were in good relations just yesterday leaded to a full-scale space war, and the main battlefield of this war becomes planet Mars.

Our hero - young and promising squad leader of a newly created Order of Crusaders – the new power, called in to stand firmly in a global chaos and give the System a chance to survive. He arrives on Mars by an order to join the Heavy Crusaders Battalion that is currently forming up – the 4th battalion – the one and only Heavy Assault Crusaders' battalion of the System!