Spielberg and Lucas aimed to make "Indiana Jones and the Temple of Doom" much darker, because of their personal moods following their respective breakups and divorces. Lucas made the film a prequel as he did not want the Nazis to be the villains again. He had ideas regarding the Monkey King and a haunted castle, but eventually created the Sankara Stones. He hired Willard Huyck and Gloria Katz to write the script as he knew of their interest in Indian culture. The major scenes that were dropped from "Raiders of the Lost Ark" were included in this film: an escape using a giant rolling gong as a shield, a fall out of a plane in a raft, and a mine cart chase. For the third film, Spielberg revisited the Monkey King and haunted castle concepts, before Lucas suggested the Holy Grail. Spielberg had previously rejected this as too ethereal, but then devised a father-son story and decided that "The Grail that everybody seeks could be a metaphor for a son seeking reconciliation with a father and a father seeking reconciliation with a son."