Complex sentence: Soon Harry, under his invisibility cloak, meets Ron during a Hogsmeade trip; when he returns, Snape catches him and confiscates his Marauder's Map.
Split into simpler sentences: Soon Harry, under his Invisibility Cloak, meets Ron during a Hogsmeade trip. Harry quickly returns to Hogwarts, but Snape catches him and confiscates his Marauder's Map.