Dejah Thoris and The Green Men of Mars Vol. 3: Red Trigger

She's faced the cannibal Thark, Voro, and he's dead. She's stopped his plot to terrorize Helium and destroy the peace between red and green people. Now, consumed with survivor's guilt, Dejah Thoris does something beyond reckless: joins a team of Thark warriors formerly under Voro's command for a suicide mission. The Princess poses as their slave to infiltrate a savage tribe of green Warhoons trekking across the Barsoomian desert to an ancient, unearthed weapon. Vastly outnumbered, they must stop the Warhoon lunatics from activating it with a psychic in their midst - and turning it on Helium!