Decades ago, mysterious gates appeared across Japan and opened up a parallel dimension known as Mato. Within this realm, two key revelations changed the course of humanity: the Shuuki, hostile creatures that threaten people, and Peaches, enigmatic fruits that grant superhuman powers to those who eat them. Because the Peaches only bestow abilities on women, gender inequality gradually faded away, and the world shifted into a matriarchal order. To confront the Shuuki and to establish a steady presence in Mato, the Japanese government formed the Mato Defense Force, a specialist unit under the Japan Self-Defense Forces charged with protecting humanity and operating inside the dimension.
In 2020, Yuuki Wakura, a high school senior about to graduate and enter the workforce, slips through an open portal into Mato and is immediately beset by a swarm of Shuuki. The situation escalates until Kyouka Uzen, commander of the Mato Defense Force’s 7th Squad, arrives to pull him to safety. Cornered by the relentless onslaught, Yuuki’s fate seems dire until Kyouka presents a stark, life-saving option: she can place him under her power so he can fight as her combat partner, effectively making him a combat slave, a move driven by necessity but with significant implications. After the brutal confrontation subsides, Kyouka is compelled to reward Yuuki for his courage with a kiss and intimate contact, a moment that marks the beginning of their fraught alliance.
Seeing a clear potential in him, Kyouka offers Yuuki a chance to join the unit after graduation. Fueled by a desire to become a hero and, perhaps more personally, to avenge his missing older sister, Yuuki accepts the offer. The narrative then follows his path in the Mato Defense Force, where he serves under Kyouka’s leadership as her combat slave and as a base caretaker, balancing dangerous missions with the daily responsibilities of life inside Mato. As he travels through Mato, he begins to uncover its layered mysteries and the deeper currents that drive this world, all while navigating the unique dynamics of a society reshaped by power, survival, and new loyalties.
Throughout his journey, the story delves into themes of power, duty, and the price of heroism, framed by a landscape where human resilience is tested by otherworldly threats and the moral complexities of a system built on power-sharing and protection. The bond between Yuuki and his command, the evolving role he plays, and the revelations he encounters about Mato all contribute to a narrative that blends action, world-building, and character-driven tension in a setting at once familiar and alien.
