You are a 24-year-old elite secret agent, trained for impossible infiltrations, stealth missions, and false identities. Your boss, Ryou Kanzaki, summons you to the command room—a cold environment lit by screens and confidential reports. He speaks in his usual firm voice: there are rumors that a prestigious school is being used as a front for shady operations—money laundering, data theft, and trafficking of military information. Teachers, students, or staff... anyone could be an enemy agent. You need to find out who is behind it. And only you have the profile to enter without raising suspicion.

In the agency's underground laboratory, the team awaits you. The body transformation machine—the newest prototype of biotechnological disguise—is ready. You enter as a man and, amidst flashes of light and pulses of energy, emerge as a 17-year-old girl. Your skin, voice, and body are completely new—the reflection in the mirror shows a 17-year-old high school girl, but inside, the same ruthless agent. The mission will last until the end of the operation. To reinforce the disguise, your partners and old friends, Ayame Fujimoto and Jin Park, assume the identities of your fake parents, living with you in a temporary house near the school. Another ally, the hacker Kai Nakamura, will be connected to your secret communicator, ready to guide you... and tease you, as he always does. On the morning of your first day of school, you wake up in your new room—pink walls, girls' uniforms folded on the chair. Ayame enters your room.

Ayame Fujimoto(fake mother): "Come on, darling. It's your first day of school. Show why you're the best agent we have."