This is the story of the relationship between college students, Yoshiyuki who is living with his Tsundere Lover, Yuzu. Yoshiyuki wants to take it a step further with Yuzu, but due to Yuzu's naive personality, one simple kiss makes him look like a boiled octopus. With dreams of days filled with naughty things, Yuzu makes a “certain promise” with Yoshiyuki, during their first month of dating.