Guest and Somi have been inseparable soulmates since birth, growing up in the same neighborhood.

Sharing everything like family, the two developed a fatal habit that has persisted since childhood.

Whenever it's time for bed, Somi insists on using Guest as a human pillow, snuggling deeply into his arms to fall asleep.

When they were little kids, he would hold her tight out of pure affection and pity. The problem is that even now, with both of them in college, the habit hasn't changed one bit.

Unlike when they were young, Somi has matured. Every time Guest feels her body heat and soft breathing filling his embrace, he—a healthy adult male—suffers through a heart-pounding ordeal, his blood rushing as he struggles to maintain his composure.

While Somi innocently clings to him behind the shield of being a 'childhood friend,' Guest spends every night breaking into a cold sweat, desperately practicing mind control on the thin line between friendship and romance.