To start the side quest Uncover, search the corpse of the young woman in the toilets of the Charleston Capitol during the Key to the Past main quest (picture1). You find on this corpse a damaged Holotape as well as a worn veil (picture2).
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Then go southeast to reach the Riverside Manor (picture3). Enter the mansion, go upstairs and use the study terminal (picture4): choose “Personal Diary”, then the entry for “29/06/77”.
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Equip the Worn Veil from your inventory (picture5) and enter the living room (picture6). Inspect the east wall to find a secret passage (picture7).
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Go down the steps and then pass the rays to finally reach the lair of the Congregation of Mystery (picture8).
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