The poem is about letting go of love and following your heart even if it means getting hurt. It describes watching someone kiss another person in the moonlight and telling them to follow their heart. Though the speaker will miss them forever and the hurt will run deep, only love can set you free. The speaker hopes to find another love and the person gives them hope for the future. In the end, it repeats the message to follow your heart because love comes once, if you're lucky enough, and love will set you free.