Fire Time

Ishtar is a planet with three suns (the main sun, a dwarf sun, and a wandering sun) where humans and the indigenous centauroid aliens co-exist. At intervals, the wandering sun comes too close and causes "Firetime." Civilization has always collapsed at these times, due in large part to the "barbarian" Ishtarians whose lands are the hardest hit when the rogue sun comes around. They leave their baked homelands and go rampaging into the more "civilized" lands elsewhere on the planet. This time around, the humans are experiencing their first Firetime, and they try to stop civilization from being destroyed yet again