ThunderCats - Season 1 Episode 10 -

Lion-O and Snarf stumble upon a portable jail cell, and mistakenly open it up. Three of the galaxy's worst villains escape. One of them, a slick thief, manages to steal Lion-O's sword. Lion-O helps Mandora, the inter-stellar police officer that imprisoned the villains, recapture them, and return them to their cells.