This documentary tells the story of the creation and cultural impact of the world's most famous Christmas carol, composed in 1818 in Salzburg, Austria, and since then translated into about 140 languages.

In 1818, when Joseph Mohr is assigned to be the new assistant priest in Oberndorf, a small Austrian town near Salzburg, the young man is full of ideas and ideals. His passion to bring the church closer to the common people sets him on a collision course with his new superior, Father Nostler. When Mohr organizes a church choir that includes outcasts from the local tavern and performs in German instead of Latin, Nostler threatens him with disciplinary action. Their relationship further deteriorates when Maria a regular tavern patron, surprisingly joins the performance of the all-male church choir. As Mohr's initial successes start to crumble and his efforts backfire on him, he loses all hope and faces a trial of faith. The night before Christmas, Mohr has to decide if he will accept defeat and leave Oberndorf or embrace the true significance of the Holy Night.

A deranged masked Santa-Slayer comes to town for some yuletide-terror. He leaves behind a bloody trail of mutilated bodies as he hunts his way to the front steps of the town's most feared and notorious home.

A mouse from the streets and a church mouse try to help a priest and an organist save Christmas by composing a Christmas carol.

In November 1937, Judy Garland sang "Silent Night, Holy Night" with the St. Luke's Episcopal Church Choristers of Long Beach, California. MGM filmed the event in color for use in their 1937 Christmas trailer. The trailer opens with a shot of a small rural church in the snow, lighted up in the dark of night - a Christmas card effect. The camera then moves inside where we see Judy singing at the front of the choir.