​Princess Mayuka, sent to Earth after her family’s overthrow, seeks help from college student Yoshizumi. But a fateful crash landing leads to Mayuka being brainwashed into thinking she is his younger sister. Their unlikely bond grows and Yoshizumi decides to assist Mayuka in awakening the powers of Akiho, the Ultimate Weapon. With red hair, green eyes, and an insatiable appetite, Akiho holds incredible power waiting to be unleashed. Together, they embark on a mission to utilize “primitive stimulation” to unlock Akiho’s dormant abilities. Prepare for a thrilling and alluring journey as these characters explore their desires and unleash a power that could change everything.​