Masukawa Karato, being the offspring of a well-known biology professor, frequently finds himself as a subject of experimentation during mealtime. One fateful day, Karato rushes to school and unwittingly ingests one of his father's sample dishes. Soon after, he experiences discomfort and eventually collapses upon returning home. His chest protrudes, and a bundle of string unexpectedly bursts forth, shaping into the likeness of a lovely young woman. She declares Karato as her host and commences her task of safeguarding and tending to him.
