New-Slain Knight by Deborah Grabien

Couple Ringan and Penny are looking forward to spending a few weeks of quality time together. Unfortunately, Ringan is enlisted to watch his thirteen-year-old niece, Becca, a promising violinist. They decide to travel to Cornwall for a vacation, staying with Ringan's old friend, Gowan, who is a musician like Ringan. While there, both Penny and Becca start hearing voices and having visions of what looks to be a murder after hearing a folk song. In order for their lives to go back to normal, they must figure out exactly who is trying to communicate with them about deaths that happened centuries ago. New-Slain Knight is the fifth book in Grabien's Haunted Ballads series and reminded me of the ballad mysteries written by Sharyn McCrumb.