Ugarte explains his plan to leave Casablanca once and for all:Ugarte: You despise me, don""t you?Rick: Well, if I gave you any thought, I probably would." Luke was curious, but was told "to forget it." He then changed the subject and proposed applying to the Academy, instead of staying on for another harvest season, but his uncle insisted on Luke remaining for another year." But Vader hurled his lightsaber at the railing support holding Luke, and he toppled to the floor.As Luke hid, Vader stalked him and advised: "Give yourself to the dark side.It is the only way you can save your friends." He hen read Luke""s thoughts, learning that he had a twin sister: "Obi-Wan was wise to hide her from me.It seemed to me I stood by the iron gate leading to the drive, and for a while I could not enter for he way was barred to me.