Siberian Mayhem follows Sam 'Serious' Stone in Russia, before the ending of the last game as he attempts to chase down the traitor General Brand. This mission spans five levels that are each relatively long and filled with enemies and ammo, and plenty of secrets to make exploration worthwhile. These secrets can be special pieces of equipment that truly can change the course of a battle and information to help fill in the story. You will also encounter new enemy types and allies to help you cross dangerous terrain and reach your target.