Nakagawa Airi is a fragile girl born prematurely, living with a rare illness called Hypostenic Paralysis Syndrome, a condition that causes her body to shut down when her strength runs out, leaving her in intense pain. Orphaned since birth, her life is filled with restrictions and quiet suffering.

Her only family is her older brother, Nakagawa Rui—a brilliant yet cold tech genius to the outside world, but fiercely protective toward Airi. To him, the world is far too dangerous to let her face alone.

Yet Airi longs for independence. She wants to be trusted, to be seen as normal, even if her body often betrays her.

When an unexpected incident shatters Rui’s careful control, Airi begins to see both her brother and the world differently. As danger strikes without warning, she learns that protection always comes at a price—and that sacrifice is never painless.

This is a story of weakness, devotion, and the cost of love in a cruel world.