From Wookieepedia, the Star Wars wiki.

The Sith in the Shadow
Attribution
Writer	Bob Harris
Penciller	Jerome Opeña
Letterer	Steve Dutro
Colorist	Dave Nestelle
Publication information
Publisher	Dark Horse Comics
General information
Era	Rise of the Empire era
Part of	Star Wars Tales
Published in	Star Wars Tales 13

[Source]

The Sith in the Shadow is a comic that appeared in Star Wars Tales 13 and was collected in Star Wars Tales Volume 4.

Plot summary

Mace Windu and an unnamed apprentice travelled to a planet where the natives practice the Sith religion. The natives attempted to attack when learning the two were Jedi but relented when Mace gave them a gift. Soon after Master Windu informed the Padawan that it was time to investigate a nearby temple with a great presence in the Force. The young Padawan ignited his lightsaber and headed into it. Inside, the apprentice saw a creature and attacked it. He was unaware that the creature was actually Master Windu, who blocked the student's attack and informed him that he had failed in his training. The reason for this failing is because the Padawan assumed that since the temple was a Sith temple, everything inside must have been evil.

Appearances