Helen Susan Swift 
Guardian Of The Dark Slap [EPUB ebook] 

Scottish Borders, 1921. When Eleanor Armstrong and her brother Thomas move from Edinburgh to the old house of Anton’s Walls, they hope to give Thomas peace from the shell-shock that damaged his mind. Instead, they find a community that refuses to accept incomers and a house with an evil past.
Scottish Borders, 1321. Newly knighted Sir Andrew Douglas hopes for glory and adventure when he ventures to the crusades, but is diverted to fight the rogue knight Hugo de Soulis at Caercorbie.
Past and present combine in this dark tale of necromancy and demons amongst the moorland and hills of rural Scotland. Can Eleanor and Thomas overcome an ancient, powerful evil?