This song is basically about making sure you value the ones you love before they are gone, and how being apart from them makea you not feel whole "The pieces of my heart are missing you". In the music video it shows three examples;
There is an old man who's wife died and he is sad and lonely. It shows him felling her clothes and looking at wedding pictures and such.
There is a teenage couple out in the woods (?), and the girl's mother drives out and makes her leave. Later when the girl is in her room, she takes out her camera and looks at some pictures she took of them and him.
Then there is a young married couple. The husband is in a uniform and headed off to war, and it shows him getting on the bus with other young men. After he leaves you see that the wife is pregnant. Later it shows her watching the news and seeing all the destruction, and checking her phone to see no new messages. At the end of the song it shows that she got a text from him saying he is okay.
