Satou Matsuzaka is a high school student famous for her stunning looks and her tendency to be easily influenced by men. But everything changes when she meets Shio Koube, a young girl with whom Satou falls deeply in love for the first time. To keep their living situation a secret, Satou tells others that she lives with her aunt, but in reality, she shares an apartment with Shio in hiding. Despite her innocent appearance, Satou will go to great lengths to protect her beloved and ensure their "happy sugar life" remains intact.