Genderbent Hero and Genderbent Demon Lord

The hero Airu (アイル) and his companions fight against the Demon King, but are defeated. Driven into a corner, Airu uses an item called the "Parutea Branch" (パルテアの枝) in an attempt to turn the tide of battle.

But when he wakes up, he discovers that he has traveled back two years into the past, to the very beginning of his journey, and he has been turned into a girl. Though initially surprised by the change, she quickly accepts her new situation and decides to enjoy her new life as a girl. Elsewhere, at the demon castle, the Demon King finds himself in a similar situation where he has also been turned into a girl.