Keeping Secrets is a Document in the Rise of the Tomb Raider: 20 Year Celebration DLC Blood Ties. It belongs to the Lord Croft's Journals set and contains an account of the renovations that Lara's father did in the manor.
I've been careless with presenting my findings - attracting all the wrong sorts of attention. Roth thinks I'm being paranoid by building this secret vault, but I know I'm being watched. My work is too important... and potentially dangerous... it can't fall into the wrong hands.I need a secure place to keep it all safe.