Ok so I'm beseeching the boards today because I guess I'm just unlucky as hell.

When I got the "Shalidor's Insights" quest, the first book spawned in Shroud Hearth Barrow. Coincidentally, I'd already cleared this entire dungeon (Shout Wall included) so I'm thinking 'piece of cake', right?!

Wrong. I got as far as the pendulum trap and there is a locked door that tells me I need some specific key. I combed the entire dungeon up to this point several times, and I can't find that blasted key!! Am I supposed to have a companion with me or something? I can't find a solution this this anywhere on the internet.

Please help, mighty forum sages! XD