The Lillian Girls' Academy students have commenced their summer break with the arrival of the summer season. Yumi and Sachiko plan to spend their vacation in the Ogasawara family's summer home, but their tranquil plans take a negative turn upon unexpected visits from Sachiko's former acquaintances. These privileged and arrogant debutantes hold the belief that Yumi is unworthy of Sachiko's attention and aim to make this summer a regrettable one for her.