With her innate infinite magical power, Issuer has been responsible for supplying magical power to the entire hero party as a mana porter. However, one day he is suddenly expelled from the party for an unreasonable reason. Ishua is disappointed when he sees Aria, a saintly girl who has been following him. In fact, her expulsion was the hero's own decision, and she thought that Yeshua had abandoned them, so she came to take him back. After learning the truth about her, Aria decides to leave the party, and Ishua begins his journey with her. The strongest mana porter was banished and the hero who banished him. The contrasting adventures of these two begin now!!