Lucía was sitting on a park bench, staring into the horizon. It was February 14, Valentine's Day, and around him he saw couples holding hands, laughing and sharing moments of complicity. She felt alone and hopeless. She had recently broken up with her boyfriend, and the day of love only reminded her of her loneliness.

As she watched the couples stroll, an old man approached her. With a kind smile, he held out a red rose to her and said, "On this proposed day, let your...