The Barcaldine Castle is a 16th-century castle in Benderloch, near Oban. It's said to be haunted by two phantoms: Harriet Campbell, also known as 'The Blue Lady', who appears in her room and has been seen playing the piano on windy nights. A separate phantom is believed to be Donald, the brother of Sir Duncan, who initially appeared to warn his brother about a visitor, but later lingered to scare guests and staff.

Built by Sir Duncan Campbell in the 16th century, Barcaldine Castle has a long history of ghostly encounters. According to local legend, Donald, Sir Duncan's brother, was killed by his friend Stewart of Appin after providing him with free board and food. The castle's complex past is said to have created a unique energy that continues to manifest itself in paranormal activity.