Capt. W.E. Johns 
Biggles and the Penitent Thief [EPUB ebook] 

What connexion could the theft of jewels worth a quarter of a million pounds from a shop in Regent Street, London, possibly have with a remote island off the coast of Labrador? The long trail that brought Biggles so far, with Bertie, Ginger and young Tommy Miller, was not ended when they touched down at Rankinton. Both Jack Fraser, the Mountie, and Angus Campbell, the silver fox farmer, were allies worth having when Biggles came up against the villainy of Raulstein and his American gunmen.