Every day the 89-year-old Maria Zabova climbs 220 steps to reach the 12 bells of "Alexander Nevski" Catherdral, to get their 23 tons of bronze moving and to beckon the faithfulls to the temple. Ten years ago, scientists from the Bulgarian Academy of Sciences started researching the miracle sound of the bells, which is like no other instrument's. Some 150 years ago the family of Victor Limonov started casting bells - and continues to this day. "The Music of Sofia" is a story about people who breathe life into a fading art, about their passion, the voices of 12 bells and whether we still hear them or not.