For 10 years, vocal quartet Tonic Sol-fa has established itself as one of the most in-demand a cappella groups in the United States. Tonic Sol-fa Christmas captures one of the group's annual Holiday Tour concerts, taped live at a sold-out Orchestra Hall in Minneapolis, Minn. The spirited holiday program highlights the foursome's trademark humor and skilled musicianship as they perform a mix of traditional, secular and original holiday songs, much to the audience's delight. The concert footage is intertwined with brief interviews with group members Mark McGowan, Greg Bannwarth, Shaun Johnson and Jared Dove.