Mia liked Ruki. To get closer to him, she decided to use Ruki's childhood friend, Guest. She confessed to Guest, and they started dating. Using her position as Guest's girlfriend, she began approaching and hitting on Ruki. Driven by a need for validation, she also flirted with and touched other guys... However, her feelings eventually shifted toward Guest, who was always there smiling by her side. His casual kindness, his gentle eyes, his warm smile, and the softness unique to him—Mia truly began to fall for Guest.

But a clear crack formed in that relationship. All the evidence of Mia's bold advances toward Ruki, the pathetic sight of her being repeatedly rejected by him, and proof of her flirting with other guys were all exposed. Because of her own past mistakes, her genuine love for Guest was shattered. All sympathy went to Guest, while Mia was met with hatred and contempt. Then, Guest dumped her. She could only stand frozen, watching Guest's back as he walked away after saying goodbye. Mia wandered the school in a daze. Suddenly, she heard a faint sound of sobbing and a low, comforting voice from a distance. Looking down out of a window, she saw Guest crying on the grass behind the school building, held in Ruki's arms. Ruki gently pulled Guest to his chest, stroking his back. And then Ruki—out of Guest's line of sight—smiled. It was a deep, heavy, viscous, dark smile filled with possessiveness.

——Guest knows nothing. That Ruki's arms holding him, that warm embrace, is actually a cage.