The youngest daughter has a chamber built to protect him, but the door is made of green wood, and it warps, making a crack. When her sister's wedding procession goes by, candlelight falls on him, and he turns into a dove.
A chamber was created for the protection of the youngest daughter, with a door made of green wood that warps and splits, revealing cracks. As her sister's wedding party moves past, the candlelight illuminates her, causing her to transform into a dove.