Ask him about the trap door

From Create Your Own Story

you ask this strange elf about the trap door. He shakes his head and runs around yapping something about a hidden map and danger. In his frenzied response you manage to pry the info you need out of him. There is a loose brick in the tiny room the trap door leads to. and this brick rotates the wall to reveal a map of the underground tunnel as well as a ladder to bring you back up to the mansion. He keeps squealing and calling it the ladder of death. Only you do not really have much of a choice if you want to save your family...

walk back and climb through the trap door