This was a good movie but if you have read the book you will notice there are a variety of things that were changed and left out of the movie... Although it was Luke who stole the Lighting Bolt from Zeus, it was Kronos (the Titan God and father of Zeus, Poseiden, and Hades) he was serving, not Hades. Ares also played a role in it too. When Ares captured Luke for stealing not only the bolt but Hades helm, he started having dreams of Kronos and released Luke and kept the items until Percy came along and placed them in his possession by the means of a backpack, not a shield. The flying shoes were cursed and were supposed to lead Percy to Tartarus to give the items to Kronos to start a war between the gods and return him to power. It was Percy's mother who was left behind in the Underworld, not Grover, and Hades returned her once he received his helm back. Percy fought Ares before returning the lightening bolt to Zeus, not Luke, and afterwards he gave the helm the Mrs. Dodds (one of the Furies) to return to Hades. Percy didn't find out who his father was until after he reached the summer camp at Half-Blood Hill during Capture the Flag when he fought Clarisse. Also, Percy received the pearls from a sea spirit in the book.