Lachlan Gilmore rescues a lady whose cart has become stuck in a ditch, but unbeknownst to him, Lady Annabel Erskine has a secret mission: to keep Mary, Queen of Scots, imprisoned on Castle Island in Lochleven. Soon, Lachlan's sister, talented seamstress Christina, is assisting Lady Annabel in her work. But as their friendship grows, she is unwittingly drawn deeper into the doomed Queen's affairs.