In recent time the birth rate of certain races was drastically low, and due to this the government decided to intervene. They devised a new system where a computer would assign people to each other with the only goal being to conceive and have children. Unfortunately for a certain teacher, he was assigned a student of his… and not just any student either, this student is a blonde elven princess named Iris.

Iris has been issued a bodyguard to maintain her safety while she attends her school. It just so happens that this bodyguard is also another blonde bombshell elf that has eyes for the luckiest teacher ever. After having sex while leaning over the bed of Iris, she awakens to fill them in that she heard every single bit… And so a threesome of unparalleled quality begins…

After the massive success with Iris and Aegis, a new member of royalty is assigned to the school. The Empress of the dragons is a problem child who looks down upon others races. After getting alone with our protagonist she comments on his sexual prowess and decides to have a piece of him herself.

After being exhausted by all 3 of the students wanting his sexual energy daily, our protagonist feels at though he is at his limit. Soon after he gets a call to meet up with the three of them and is told that he has to choose just one...but can he really choose JUST one?

The Ark Academy, chosen as a model case for inter-species school integration, welcomed a new transfer student, Elliott Leukosia, a popular member of a mermaid idol group. Elliott, with her delicate appearance and shy demeanor, quickly became adored by her classmates. However, she had a problem. Due to the characteristics of her mermaid species, her body would soon masculinize. "I transferred here to get your help, coach..." With her developing body, budding breasts, and slender waist, Elliott, with her innocent eyes, pleaded for 'Assistance.' The homeroom teacher, torn between desire and ethics, couldn't refuse... The mermaid's 'song' permeated his consciousness. A mermaid idol surpassing the popularity of AKB48 and TWICE is born! With her clear singing voice, your baton will also reach a forte!

The Ark Academy's transfer student, Origamine Ouka, was the homeroom teacher's childhood friend and the princess priestess of the oni clan. Though she used to be like a little sister to him, upon reuniting after several years, she witnessed him performing 'Assistance' with a student and exploded in anger. Ouka sealed the teacher's manhood with an oni spell. "You are tainted, brother." Unable to perform 'Assistance,' the teacher tried to persuade her, but Ouka was adamant. As a last resort, he decided to gently unravel her heart, which had been restrained as a princess and a priestess, with his kindness as a childhood friend and a teacher. Sweet moans unimaginable from her dignified demeanor, and her ample breasts released from her solemn kimono. What was supposed to be a sex-filled time in the absence of the oni turned into tears in the eyes of the oni! With more intense service scenes than ever, it's a golden club for the oni!

The Ark Academy, chosen as a model case for inter-species school integration, saw the elf Aegis Thea Eaderlindt and her teacher head to the beach at her invitation. With her dignified and beautiful face, toned body, and ample chest, she attracted the gazes of men on the beach. Posing as the teacher's girlfriend to ward off pick-up artists, Aegis's attractive body made it impossible for him to suppress his desires. "This isn't Assistance, just a lovers' rendezvous..." With this pretext, the two intertwined their bodies passionately, knowing they would return to their usual relationship back at school. What are the hidden feelings of the elf knight under her cool demeanor? The blue sea, white sandy beach, the scent of the sea breeze... and the voluptuous guardian knight in a bikini.

The Ark Academy, chosen as a model case for inter-species school integration, saw the teacher worried about Ursula, who hadn't been attending school. He found her in the nightlife district, dressed provocatively in her school uniform. As he tried to bring her back from her dangerous activities, Ursula toyed with him. Her intense teasing and the passionate intercourse with her transformed body left him inescapably pleasured. Ursula whispered to him, "Forget everything and become mine." With her voluptuous body and seductive allure, she made him forget his resistance. Torn between his desires as a man and his duty as a teacher, what future does he choose? What are the true feelings of Ursula, the dragon princess? Can your stamina withstand the ultimate weapon of Ursula's enormous breasts?

The Ark Academy, chosen as a model case for inter-species school integration, saw the teacher helping out Elliott Leukosia, a mermaid idol from the group 'Aqua Marina,' for a day. "Sorry, coach. It was supposed to be just one day, but..." It turned out to be a multi-day tour, a "dreamy bus tour where you can have sex with active idols from morning till night"! With busty tanned gyaru idol Ella, the naturally fluffy idol Elsie, and the slender and delicate Elliott, the teacher spent days immersed in sex with the three beautiful idols, losing his rationality to their mermaid songs. "A bus tour where you can have sex with three active mermaid idols from morning till night." Ready for launch!? Why does the bus shake even when it's stopped?

Origamine Ouka is the leader of the Origamine clan, a family of demons. She works on exorcising the “demons” that are spreading throughout the world while also attending school. Her husband, the protagonist, also helps Ouka in her work and has an important mission: to have children with her for the sake of their clan.