Tranquility has settled across both worlds, and each person continues their ordinary daily routines. Yet how ordinary can existence appear for combat veteran Kazuki, who cohabits with five stunning companions beneath a single roof? It seems he need not wait long to discover. A relic of antiquity, the gateway to their escapades across alternate realities, compels Kazuki once more to mount the ride—this time into the cosmos or nothing in the void, beyond known horizons.