(I am uncertain where part 1 ends and part 2 begins, so I have taken my best guess)
Artoo jumps off the harem tower and uses his parachute to land in a dump truck. Mungo Baobab, using the saw he was given by Fidge has just about managed to finish cutting through the bars of his cell when Admiral Screed and some stormtroopers arrive with a droid to put Mungo into hibernation for his trip to the Emperor.
Admiral Screed and company are hit by a barrage of rocks thrown by Fidge, who is in the near by pipe. Mungo uses the distraction to kick out the precut bars and escape down the pipe with Fidge. The troops shoot at the pipe, destroying the entrance to the pipe and allowing Mungo and Fidge to escape.
Meanwhile Artoo searching for Threepio comes upon the droid who was the Great Heaps latest victim. Artoo is unable to supply enough power to revive her. Artoo is soon captured by the the Great Heap's (who is apparently the main component in a foundry) magnet, but Artoo pulls the plug supplying power to the Great Heap's magnet, allowing him to escape into the foundry.
Threepio is strapped to a table, while a droid is preparing to take him apart. Threepio manages to get one of his arms free and hits a lever which causes the table to elevate to the very high ceiling, at which point the straps are released and the table tilts causing Threepio to be dumped onto a conveyor belt, leading to crushing doors. Artoo ends up in the same room and leaps on to the conveyer belt with Threepio and cuts a hole in the wall, through which the two escape down a slide and into a metal cylinder, which is then seal by the Great Heap and thrown into a chamber with lasers that are destroying the items with in. Artoo manages to open the cylinder and gets on the inside wall of the cylinder, running it like a barrel up the wall and out the window.
Since Mungo cannot fly the ship, he must get Artoo or another Artoo unit to assist. Fidge and his pet, Chubb go down one of the pipes in an attempt to free Artoo from the harem.
Mungo in an attempt to get onto the cargo ship jumps into a garbage container, just as Artoo and Threepio slide into the same container. There he overhears Admiral Screed's order that only droids be let on board. Mungo comes up with the idea to use the ships turbo lasers to destroy the moisture eater and disguises himself as a droid to sneak on board the cargo ship with Artoo and Threepio.
Fidge manages get into a bulldozer, but he is unable to control it and it ends up on the edge of a cliff. Lucky, Fidge is figures out how to work the controls, and moves the bulldozer forward and avert danger. He procedes to smash through the wall of the harem freeing the droids.
Once aboard the ship, Artoo patches into the drive system, but it sets off an alarm, alerting Admiral Screed. Mungo still disguised as a droid delays the troops, with droid type complaints long enough for Artoo to take off, leaving Mungo and Threepio on the ground.
Admiral Screed orders the cannons to fire on Artoo's commandeered cargo ship, while the freed Artoo units chase away the stormtroopers. Fidge still driving the bulldozer smashes into the legs of the cannons, thus disabling them.
Artoo dumps the ore while shooting the moisture eater, but to little effect. The Great Heap calls Destroctover, two droids, one blue one red who "transform" into several configurations, finally making a speeder bike mounted gun and proceed to fire on Artoo's cargo ship damaging it. Artoo fires back and in the confusion the Destroctover smashes into a wall, breaking it into 10 small droids who scatter.
The Great Heap picks up a large metal disk and throws it at Artoo's ship which then begins to lose altitude, and Artoo crashes it into the moisture eater, destroying both it and the ship.
Threepio attempts to go after the Great Heap himself to get revenge for Artoo, but is held back by Mungo. Next shown is a close up of Threepio's face, who seems to be crying. Rain has begun to fall, and the great heap strikes out at Mungo and Threepio, but his arm falls off and he shuts down due to the rain.
The next day the Imperial forces are made to help the farmers restore their crops. Threepio listens to the sonic capsule that plays Artoo's voice, only to have Artoo return over the hill, dragging his parachute. The last droid victim of the Great Heap lays inactive, and Artoo and the other Artoo units link together and recharge the droid back to life.
"I do so love a happy ending" – See Threepio