S5·E11 Ghosts of Christmas Past

On Christmas Eve, Harm pays his annual visit to the Vietnam Memorial to honor his father who was shot down on Christmas Eve, 1969. At the memorial, Harm meets a beautiful, but mysterious woman, who claims to have known Harm, Sr. She used to be a singer in a traveling USO tour and she met Harm's father shortly before his fateful flight.

In an unusual casting twist, Harm stars as his father in this episode, and many familiar faces show up playing different roles.