Complex sentence: On said birthday, Melody finds the locket with her name, and questions Ariel about it and get into and argument, and before Ariel can apologize and explain, Melody runs away from the castle in a boat.
Split into simpler sentences: On said birthday, Melody finds the locket with her name, and questions Ariel about it. Ariel and Melody argue, and before Ariel can apologize and explain, Melody runs away from the castle in a boat.