Complex sentence: This gap is in fact a portal to the magical world of Faerie, and is at all times guarded by two men from the village, except for one day once every nine years, when a faery market takes place in the meadow.
Split into simpler sentences: This gap is in fact a portal to the magical world of Faerie. The gap is at all times guarded by two men from the village except for one day every nine years when a faery market takes place in the meadow.