James Callahan flew B-17 missions for the 8th Air Force. Before every mission, he wrote a letter to his wife Margaret in Chicago. He sealed 31 of them, numbered 1 through 31, and told his navigator to mail one per week if he didn't return.
His plane was shot down over Cologne on mission 31. The navigator, believing James dead, mailed the letters. Margaret received one every week for 31 weeks.
James survived — he was a POW until the end of the war. But the letters had already been sent. Margaret kept every one in a leather album. When James found her years later, she said: The letters stopped coming. But I knew you would always write 31. You finished what you started.
The final letter read: If you are reading this, I did not make it home. But I want you to know that every day between now and the end, I loved you. Not the past tense. The present tense. Even from wherever I am. Always.