Next door, Yui is a single mother who divorced and is raising her child alone. I'm in the same situation, and since we're both single parents, she starts asking me for various favors. She's young and beautiful, so I can't help but feel genuinely happy when she relies on me. One day, she shows up at my door soaking wet. After a fight with her ex-husband over their child, our relationship gradually transforms into one where we can't live without each other.