Princess Leia is on her way to a meeting with the potential Rebels on Circarpous 4, but is taking heavy damage from in her ship from an energy fielf she passed though and must put down on the planet of Mimban. Luke follows her, but is distracted by a disturbance in the Force from the planet below and loses sight of her ship.
Leia Amidala Skywalker Luke Skywalker
Luke and R2-D2 soon find Leia and C-3PO. They all then discover that the Empire is secretly mining Mimban, a world that belongs to Circarpous. The tools the Empire is using for the mine is also what created the energy field that damgaed Luke and Leia's ships.
The two heroes break into a miner's supply shop and dress as one of the workers before entering the tavern. When the waiter begins to suspect that Leia's fine hands and regal bearing makes her something other than a miner, Luke smacks Leia and treats her as a newly-bought servant, still in training, which curbs the suspicion for the time being.
Luke is then identified and approached as a fellow Force-adept by an old woman named Halla. She agrees to help them steal a ship to escape in if they help her find the Kaiburr Crystal first. She gives Luke a sliver of it to prove its worth. After touching it, Luke finds that the Kaiburr Crystal increases one's influence in the Force.
As they are leaving the tavern, however, a group of miners tries to take Leia for themselves. Luke fights back, but then all of them are arrested by the Stormtroopers.
Luke and Leia tell Captain Grammel, the mine's supervisor, that they are escaped criminals from Circarpous. Grammel puts them in jail until he can check their story. He also confiscates Luke's sliver of the Kaiburr Crystal.
Inside the cell, Luke and Leia meet Hin and Kee, two Yuzzem slaves from the mine. When Halla shows up outside their window, Luke and the old woman use the Force to unlock the cell, freeing the four prisoners.
On the way to finding the crystal, the party comes across a Wandrella, a large swamp worm with teeth. Luke and Leia lose it down a well, but are then forced to follow a tunnel in the well since they have no way of getting back up.
In the meantime, Captain Grammel has informed Darth Vader of Luke and Leia's presence and the Dark Lord has arrived to personally lead the search for them.
Halla and the droids are captured above ground by Coway and Luke and Leia are captured by Coway in the tunnel. Both groups are brought to the underground Coway village and Luke is made to fight the Coway champion in order to secure their release.
a few Coway
When Luke wins, the Coway honor the party with a feast. Suddenly, though, Luke sense Vader approaching and is elected to lead the Coway in battle against Vader and his troopers.
The Coway and party win, forcing Vader and his forces to withdraw from the tunnels, but Vader has now sensed the presence of the Kaiburr Crystal and is on his way to claim it for himself. On the way, he cuts Grammel in half for the failure in the tunnels.
The heroes find the crystal first, in the Temple of Pomojema, but Vader arrives soon after. He kills Hin and Kee and then Leia attacks him, actually landing a blow. He mortally wounds her, though, and it is Luke who cuts off Vader's arm and sends him down a hole in the temple's floor.
Halla then gives Luke the crystal and Luke is able to use it to heal Leia, after which the surviving party members are easily able to steal a ship and escape the planet.