A plague jacket is obtained during the Sheep Herder quest along with a set of plague trousers. It is bought during the quest for 100 coins from Doctor Orbon and cannot be obtained again afterward. The full set, consisting of the jacket and a pair of Plague trousers, grants access to the incinerator area north of East Ardougne. There's not much there except a respawn point of a Cattleprod, which cannot be obtained without the set. This was worn by Master Fisher before the graphical update on 23 March 2010.