Raised in a single-parent household, Kota continued to depend on Yui even after becoming a college student. Yui had spoiled him, wanting to spare him any hardship, and realized that his mother complex was her own fault. Kota is already a junior in college, but at this rate, he will never be able to function in society. Hoping it would be a catalyst for his independence, Yui invited Kota on a hot spring trip.