Full Metal Panic! Volume 4

With the defeat of Gauron, Sousuke's life has entered a comfortable rhythm.
He's adjusting to school—the occasional car bomb false alarm notwithstanding—and balancing his newly-found normalcy with the needs of his mercenary life. He's even started to turn his thoughts toward the future—a future that might involve Kaname. But that future will soon face a threat, not from North Korean soldiers, Italian mobsters, or Russian Spetsnaz... but from the hierarchy of Mithril itself!