Satou Matsuzaka learns to love for the first time after meeting Shio Koube and lives with her in a shared apartment. Publically, she tells people that she resides with her aunt in her apartment, and keeps the fact that she lives with Shio a secret.

Satou is a freshman at Makikou High School and primarily works at Cure á Cute, maintaining a kind nature and getting along well with other people in order to sustain her lifestyle with Shio. While she wishes she could spend her time with Shio forever in their apartment, she is aware of the fact that they cannot live on peacefully if she does not work and earn money for food, utilities, etc. Because of this, Satou often has to confront the outside world where people interfere with her relationship due to her past history of accepting anyone who has confessed to her and changing partners every three days. Satou is prone to severe animosity when people disrupt her relationship with their interpretation of "love," and can be easily provoked when it comes to Shio due to her overprotectiveness. She is willing to take any action necessary to eliminate threats to Shio and their "Happy Sugar Life."