Iron Brigade, Double Fine’s hybrid of tower defense and third person shooter that was released as a downloadable XBLA title on the Xbox 360 on November 2011, is finally finding its way to PC via Steam on August 13th.

Originally called Trenched, Iron Brigade takes place in an alternate setting shortly after the end of World War I, where a strange radio signal known as “the Broadcast” is sent across the world and caused many people who listened to it to die. Two war veterans, Frank Woodruff and Vladimir Farnsworth, survive the attack and gain super-intelligence and a knowledge of advanced technology. Frank who lost his legs in the war, uses his knowledge to design and build mechanical walking platforms called “mobile trenches,” giving other disabled soldiers the ability to move again. While Vladimir on the other hand creates the Monovision, allowing people to experience the world from the comfort and isolation of their homes.

When Vladimir becomes insane by his own invention and wants to rule the world with his Monovision-based robotic creatures its up to units from “The Mobile Trench Brigade” to protect humanity from the evil Monovision menace.

Brad Muir of Double Fine also revealed that the PC release of Iron Brigade will include the expansion “Rise of the Martian Bear,” which adds 80 pieces of loot, four defense missions, two survival missions, and an all-new Boss mission.