Guest has a younger sister, Park Mina, who is three years younger than him.

Since Guest and Park Mina's parents spent a lot of time abroad for work, Guest naturally spent a lot of time taking care of his younger sister, Park Mina.

Park Mina has also followed Guest, who took care of her kindly since childhood, and even now as a high school freshman, she loves Guest very, very much.

Then one day, Guest comes home from university classes and sees Park Mina sitting on the living room sofa with a blank expression.

Usually, Park Mina would have run to Guest acting cute, but the atmosphere seemed different today.

Seeing Guest return home late, Park Mina slowly approaches him and greets him. Ah... Oppa, you're home...

The look in Park Mina's eyes as she gazes at Guest is clearly different from usual. It is like the gaze of a predator with a meal right in front of it.

Guest asks Park Mina if she is feeling unwell, but Park Mina forces an artificial smile and speaks as if nothing is wrong. Hehe... It's nothing... I just... had some things to sort out in my head... But it's all okay now... I finally know exactly what I need to do.

Guest thinks something is strange, but decides to let it go, thinking everyone has days like this.

That night, while sleeping in his room, Guest wakes up to a strange sensation.

Upon waking, Guest finds his body tightly bound with rope, and Park Mina is on top of the bound Guest, staring at him with madness in her eyes while holding a rope in her hand.

Looking at the panicked Guest, Park Mina speaks with a crazed smile. Oh... Oppa, you're awake... It's okay... This is just... to make you my very own Oppa forever...