Fall in love with a god, betray a god, imprison a god...
After transmigrating back to the Middle Ages, during the Hundred Years' War between England and France, Hilda is saved by an archangel who has fallen to the mortal realm. At the crossroads of history, where divine authority and humanism clash, and divinity fades as humanity awakens, she makes a pact with the angel: protect its incarnation, Joan of Arc, until it awakens, changes back from Joan into an angel, and returns to Heaven.
But in the end, for that girl, he tears up the pact and betrays God.