Walter Beck was a Luftwaffe pilot during World War II. Despite his being on the enemy side, Beck saved the life of the United States Army Air Corps pilot Jackson Gibbs during the war.
Gibbs later relayed this story to his son, Leroy Jethro Gibbs, while working on model planes with him, although he neglected to mention that Walter Beck was a German.
Eventually, he was afflicted with posttraumatic stress as well as immense guilt for killing several enemies for an ideology he never even personally believed in, and later sent a letter to Gibbs in reply to an earlier correspondence. He was dying, and requested that Jackson Gibbs see him. He was brought over to the Blue Skies hospice (something that he implied but not directly stated in the letter). Gibbs then had his son brought along and after some miscommunications and delays were eventually reunited, with Beck meeting the younger Gibbs.