Rarely does a girl come into the world bearing two distinct souls: one human and the other belonging to a kaiju. These unique beings, known as 'Kaiju Girls,' embody human appearance fused with the supernatural might of colossal monsters. To aid these extraordinary girls in mastering their abilities and integrating into society, the International Kaiju Rescue and Mentoring Organization, GIRLS, was established. In a recent occurrence, three young girls have awakened their dormant kaiju halves. Aki Miyashita, a reserved individual, inherits the soul of Agira. Reika Shiragane, a solemn figure, is bestowed with Windom's essence. Lastly, the spirited Miku Ushimaru becomes the vessel for Miclas. United under GIRLS, these three girls undergo training to harness their powers and navigate their primal instincts. With the unwavering support of their peers, Agira, Windom, and Miclas embark on a journey of self-discovery, unraveling the essence of being a Kaiju Girl.