"Across the Roon Sea" is the twelfth episode of the Star Wars: Droids animated television series, and the twelfth episode in season one. Written by Sharman DiVono from a story by Ben Burtt, the episode originally aired on ABC on November 23, 1985.
Mungo Baobab plans to head home to Manda empty-handed. C-3PO tries to reassure Mungo that although they didn't find any Roonstones, they did find friends. The Imperials spy on them, and Admiral Screed once again scolds Governor Koong for not recovering the Roonstones.
Auren and Nilz Yomm return with a Roonstone for Mungo. They tell him to speak to the hermit "Old Ogger", an old prospector, to learn more. The Imperials follow them.
Auren, Mungo and the droids take shelter from the rain in an old agricultural freighter. Inside, they discover "Old Ogger," who turns out to be Mungo's great-uncle, Oggem Baobab, who left sixty years previously on a quest to find the Roonstones. Oggem turns his quest over to Mungo, warns him to put family and friends before treasure, and dies.
Mungo goes through the bag Oggem left him, which contains clues to find the source of the Roonstones. Auren tries to talk him out of it, since he has enough Roonstones without finding the source, but Mungo insists on riding off to the nearest settlement to find supplies.
Koong tracks Mungo to the inn where they are negotiating a trade. Gaff arrives and tries to capture them, but Mungo uses a seed launcher to create fast-growing vines that entangle their enemies. Unfortunately, the Rockhoppers carrying the Roonstones start to run away, and while Mungo tries to catch them, he lets his friends get captured. Only Artoo escapes.
The Imperials take Mungo, Auren and Threepio away on a ship, where Threepio is tormented by Lin-D, an entertainment droid who tells jokes incessantly. Artoo swims after the ship, climbs on board and frees the prisoners, who overpower the guards.
Mungo goes after the Roonstones despite Auren's objections; when Gaff tries to shoot him, he sets the ship on fire. Mungo and the other prisoners escape in a lifeboat and head into a storm. Koong sends fighters after them, which Mungo easily destroys; the ship's sail falls onto Lin-D, however.
Koong's ship catches up, and the lifeboat is headed for a whirlpool. They fashion a replacement sail for the boat, but must thrown the Roonstones overboard to escape.
Screed rebukes Koong once again. Mungo, having learned an important lesson about friendship, plans to look for the source of the Roonstones.