Once upon a time, a "big portal" opened between the other world and the human world, through which various other-sex creatures flowed into the human world. The one-way "great portal" kept the otherworldly creatures in the human world, where they began to coexist with humans. The angel tribe, unable to return to their original world, continue to search for the "great portal to return to", but they arrive at a certain young man...? Long-awaited prequel to "New World Lovetopia", the angel version!