While working part-time at a bustling bentō shop and raising her son, I Sayama, with her naturally cheerful and vibrant personality, manages to make the shop a success, attracting many customers. Although they are not wealthy, she and her son live happily together. One day, Mukai, a part-time student working at the shop, suddenly confesses his love to I. This unexpected confession rekindles the excitement of being a woman after years of suppression, and they eventually end up having intense and passionate sex in a hotel. Since then, I has forgotten her role as a mother and is deeply immersed in her fiery love for Mukai, while harboring underlying concerns about their relationship.