I love secret passages and secret places in houses. Currently writing another vampire series,not related to this one. The main character inherits estates with a small mansion. There is a mausoleum on the estates. The secret rooms are not in the mansion.
From Protector of the Grey House:
Surprised the door did not closed on its own, she looked around the entrance of the room and saw the lit keypad. The numbers were lit from underneath. The keypad was on the same side of the wall as the one in the bathroom. She entered the code again and the door slid shut. The room brightened but only a little. It was unnatural light, but she couldn’t see the source. She put out the candle, placed it on the floor and waited as her eyes adjusted. When she could see, she looked around and saw the boxes piled high. The boxes started at the wall next to the door and headed straight for a few steps then ended at a t-intersection. She rubbed her hand against her forehead and glanced down in frustration. Damn him for his paranoia.