At the Back of the North Wind by MACDONALD, George

Diamond the little boy sleeps in the hayloft above the stall of Diamond the horse. The loft is snug but drafty, and after plugging a hole in the wall one night, Diamond is scolded by the beautiful Lady North Wind for closing her window into his room. Thus begins their friendship. Spirited away by the North Wind, Diamond embarks on a series of adventures both near to and far from his home. His pure heart and his simple, loving spirit guide him as he journeys to the back of the North Wind and home again. (Summary by Meredith Hughes)