In the 1600s, MacLeod sought refuge in a monastery founded by Paul, another Immortal. There he encountered Kalas, an Immortal monk with a heavenly singing voice. When it was discovered that Kalas was routinely taking the heads of Immortals as they left the sanctuary, he was expelled from the monastery and the music that was his life. Now, Paul and his choir have been lured out of their monastery for a concert tour and MacLeod discovers that Kalas is after revenge. Meanwhile, mysterious deaths at the hospital seem linked to negligence on Anne's part. It becomes obvious that Kalas is trying to destroy MacLeod's friends before coming for him.