Irekawari no Hanayome - Minarai Shuudou Oujo Lily wa Oie ni Kaeritai

Lily, an apprentice nun, spends her days in a dilapidated convent.
On her way to the frontier to prepare for the monastery's winter preparations, she meets Cornelia, a beautiful marquise who is about to marry the Count of the Frontier.
They decide to go to the frontier territory together, but they are caught in an attack by bandits who are after her.
Lily faints while defending Cornelia, and what happens?
Friendship, love, and survival...?
A romantic comedy of differences begins when an apprentice sister and a marquise switch places!