Azorea, The Piper of the Glen — Robert E. Jacob

When an alien race, Identical to humans in every way,becomes marooned on planet earth in 16th century Scotland, it becomes a life and death struggle for Griegor, the leader of the Azoreans, to prevent an evil faction of his society from destroying the native highlanders and their peaceful way of life.

This story tells of two brothers from another world, one the leader of their race and the other a maniacal terrorist bent on their destruction, who because of the final demise of their planet, are forced to flee, ultimately becoming marooned on planet earth in 16th century Scotland. Griegor and the Azoreans attempt to destroy this evil faction before they can influence the local highlanders but are unable to do so. Cormack, the leader of this faction, is successful in embroiling the highlanders in his plot to rule this new world. Now, with the local inhabitants mixing with Cormack and his followers, it becomes impossible to differentiate between the highlanders and Cormack's people. Griegor devises an ingenious device that will help them do just that. They resolve to use this new weapon to eradicate Cormack and bring peace again to the Celtic region.