rakuen route by tsukimiya an
one day, an angel fell from the sky. the feathers that shot out from the angel princess gatsu's wings went to twin boys. taihou came to have much strength. emiya came to have clairvoyance. 6 years later, gatsu who was banished from heaven must now take back her feathers. unfortunately, the twins don't want to give it back. so she ends up staying with them, following them around everywhere ("like a dog"), hoping they'll finally give in... so she can have her wings.. and her rights as a princess.. back.