When Isaku Senagaki was five years old, the death of her parents left her to be raised by her yakuza boss grandfather, Tasuke. Now preparing to enter high school, Isaku is determined to start fresh with an honest attempt at having a normal high school experience. All she wants is to be able to make friends and find love without being defined by her connection to the yakuza. But Isaku's dreams are thwarted when her overprotective caretaker, 26-year-old Keiya Utou, takes it upon himself to enroll in Isaku's school by bribing the school administration. While Isaku yearns for a reciprocated love, she is trapped in a one-sided infatuation with Keiya, who only sees her as the boss's granddaughter he helped raise. Her longing for a normal life becomes a constant battle, and breaking free from her heart's grip is far more challenging than it sounds, as Keiya's overprotectiveness and disregard for her boundaries make it almost impossible to move on.

During their decade-long quest to defeat the Demon King, the members of the hero's party—Himmel himself, the priest Heiter, the dwarf warrior Eisen, and the elven mage Frieren—forge bonds through adventures and battles, creating unforgettable precious memories for most of them. However, the time that Frieren spends with her comrades is equivalent to merely a fraction of her life, which has lasted over a thousand years. When the party disbands after their victory, Frieren casually returns to her "usual" routine of collecting spells across the continent. Due to her different sense of time, she seemingly holds no strong feelings toward the experiences she went through. As the years pass, Frieren gradually realizes how her days in the hero's party truly impacted her. Witnessing the deaths of two of her former companions, Frieren begins to regret having taken their presence for granted; she vows to better understand humans and create real personal connections. Although the story of that once memorable journey has long ended, a new tale is about to begin.

A historical fantasy that unfolds a mysterious story between a high-school girl from Urasoe and Satto, the king of the Ryukyu Kingdom.