A young man is summoned to another world to stop the spread of "akui" and save the realm from darkness. Guided by Unasaka, a bunny-eared forest spirit, the hero begins his journey toward the royal castle. Along the way, the hero's extreme lecherous tendencies lead to various erotic encounters and strange allies, eventually leading to an intimate bond between him and Unasaka as they strive to save the world.
After washing up on a desert island, the Master and Unasaka build a raft while indulging in their desires, eventually rescuing the assassin Iroha. Upon returning to the mainland, they venture into mysterious ruins where they encounter Naia, the "Crawling Chaos." After overcoming Naia's trials and combat, they receive a divine reward and learn that the only way to save the world from the corrupting influence of "akui" is to defeat the King.
After a detour to the hedonistic My Life Town, the Hero and Naia uncover the shocking truth about their world while crossing the Illusory Meadows. They discover that their reality is a virtual simulation created to preserve humanity, and the Hero is actually a clone of the King, destined to become a sacrifice to maintain the world's balance. Despite the grim revelation, Naia vows to support the Hero as he overcomes a final trial by the knight Glabra to reach the royal capital.
Upon arriving at the royal capital, the Master and his spirit companion solidify their romantic bond with a heartfelt confession and a passionate union before facing the final challenge. The Master discovers that the King had been absorbing the world's malice to protect humanity, and by liberating this burden, he successfully saves the world. The journey concludes with the couple living happily ever after in a world restored to peace.