Context: The opening crawl reveals that Han Solo's friends are engaged in a mission to rescue the smuggler from Jabba the Hutt and that the Galactic Empire is building a new armored space station which is even larger and more powerful than the first Death Star.Near the forest moon of Endor the new Death Star is being constructed in orbit, and a command star destroyer arrives and launches a shuttle with a fighter escort -- a shuttle bearing the Dark Lord of the Sith. Fearing his arrival, the commander of the new Death Star informs Darth Vader (David Prowse, voice: James Earl Jones) that the station will be operational on schedule, but when Vader challenges this "optimistic" appraisal of the situation, the commander admits that he needs more men to accelerate construction. Darth Vader, however, informs the commander that the Emperor (Ian McDiarmid) will be arriving soon, and that he is most displeased with the commander's progress. Shaken, the commander commits to redoubling construction efforts. Vader, pleased, remarks, "the Emperor is not as forgiving as I am."Jedi Knight Luke Skywalker (Mark Hamill), Chewbacca (Peter Mayhew), Lando Calrissian (Billy Dee Williams), Princess Leia Organa (Carrie Fisher), C-3PO (Anthony Daniels), and R2-D2 (Kenny Baker) return to Tatooine to rescue Han Solo (who was encased in carbonite at the end of Star Wars: Episode V - The Empire Strikes Back) from the gangster Jabba the Hutt (voice: Larry Ward). Luke sends C-3PO and R2-D2 to Jabba's desert palace to deliver a message: In a hologram projected by R2, Luke offers to bargain with Jabba for Solo himself -- if Jabba does not, he will be destroyed. Jabba laughs at the message and refuses to give up his "favorite decoration:" Han, frozen in carbonite, hangs on a wall in Jabba's court. The two droids are sent to EV-9D9's workshop where C-3P0 is given the job of Jabba's translator and R2 will be a drink-server on Jabba's sail barge.Disguised as a bounty hunter named Boushh, Leia arrives in Jabba's court with Chewbacca in cuffs. She offers him to Jabba for a sizable bounty. After Leia dickers with Jabba over the amount and threatens him with a small thermal detonator, Jabba happily agrees to pay, impressed with the bounty hunter's nerve, and Chewbacca is imprisoned.That night, Leia sneaks into Jabba's court and frees Han from the carbonite. However, she and Solo are both captured by Jabba. Solo is imprisoned with Chewbacca and Jabba keeps Leia on display in a metal bikini and chains. Luke arrives with a final ultimatum to release Solo. Jabba again refuses and drops Luke through a trap door into a pit below his throne that houses the rancor, a fearsome beast that Jabba keeps for executions. As Leia watches in horror, she sees Lando Calrissian disguised as a palace guard. After a brief battle, Luke defeats the rancor, enraging Jabba, who declares that Luke, Solo and Chewbacca will be slowly consumed by the sarlacc -- a huge, shark-toothed, tentacled maw at the bottom of the Great Pit of Carkoon.The group is taken to the pit on Jabba's sail barge fleet and prepared for execution: Luke is the first, pushed out onto a thin plank over the pit. Luke gives R2 a short salute and a small object, Luke's new lightsaber, is launched into his hand. A battle erupts, with Luke steadily taking the fight to Jabba's men. During the battle, Leia strangles Jabba with the chain around her neck and with R2-D2's help escapes from her bonds. Solo accidentally knocks Boba Fett (Jeremy Bulloch) into the sarlacc pit. Lando is also thrown off one of the skiffs, hanging by a few cables until he's rescued from the sarlacc itself by Han and Chewbacca. Luke, having fought his way onto Jabba's sail barge, has the escaping Leia aim the deck cannon at the vehicle and sets it on automatic fire; the sail barge soon blows apart. Our heroes manage to escape before it explodes, retrieve R2 and C-3PO and zip off into the desert. 
 Question: Who is Vader's son?
Output: luke skywalker