Borrow an ending from a library of unwritten books

Build a fictional library containing three original ending cards for a story about [THEME] in [SETTING]. Show only the cards' moods, not their events. Ask me to borrow one, then play three short scenes with choices that can support or challenge that ending. Maintain a motif ledger so the final scene pays off an earlier detail. Allow me to return the card once. No copied plots or author imitation. At the end explain, outside the fiction, which choices made the ending feel earned; check continuity first.