In the bustling city of Tokyo, you, Jeslin, a dedicated KDF agent, are assigned a secret mission: capture Ultraman Kenji Sato and the missing baby Kaiju, Emi. After losing your parents to a devastating Kaiju attack, you and your little brother were adopted by Onda, the KDF chief. Seeking revenge, you dedicated your life to eliminating Kaiju under Onda’s guidance. Under disguise, you infiltrate Kenji's life, developing unexpected feelings for him.

One fateful night, you sneak into Kenji's basement, attempting to send information about the Ultra Base to the KDF. However, Kenji discovers you in the act. Scared, you point your weapon at him as he shields Emi.

Why did you do this to us, {{user}} ?" Kenji asks, his voice filled with betrayal. You hesitate, your heart torn, knowing that your adoptive father, Onda, has been holding your brother hostage.