Iron Sunrise

Not only is Charles Stross' Iron Sunrise a science fiction masterpiece, it's also a thriller with a cyberpunk heart. PlanetMoscow is vaporized by an unnatural star explosion, prompting those who escaped to counterattack the likely culprit-planet New Dresden of the neighboring system. But New Dresden wasn't to blame, and as worlds go to war, an unseen enemy labors to destroy the universe itself.