Amitie and Kylie and their families have lived a happy life since childhood, but as Eritrea slowly fell into ruin, their father contracted an incurable disease and died. Kylie was hit hard by her father's death, and then Kylie began to hate her sister and turned against her. Meanwhile, Nanoha, Fate, and Hayate are planning to go on a summer vacation trip with Arisa and Suzune.