Nanasei, a high school boy, keeps having dreams of a previous life, where he was a knight serving his master. Nanasei doubted whether those dreams were real or not, until one day, when Leo, his previous master, appears in front of him as a transfer student, Rao. Rao also has similar memories of the past life, and he innocently rejoices at the reunion with Nanasei. However, he forgot the most important thing. For Nanasei, Leo was someone he never wanted to see again.

(Source: ihr HertZ, translated)