一夜を共にした人が兄嫁になった

A fateful night ties a young woman to a rich heir. She leaves quietly afterward, unaware he's been haunted and longs to find her. She then gives birth to a child in secret. Years later, to save her son, she is forced into a marriage. Unexpectedly, she runs into the man from her past. What will she do? Will she still choose to be his brother's wife?