Complex sentence: Meanwhile, Slannen gets the giants, and the ogres come to sneak into the castle to rescue Ella and find out that Sir Edgar is poisoning the crown that Char will receive during the ceremony.
Split into simpler sentences: Meanwhile, Slannen gets the giants, and the ogres come to help as well. They rescue Ella and find out that Sir Edgar is poisoning the crown that is to be put on Char's head in the ceremony.