The Mystery of the Three Skeleton Keys

After enjoying the successful conclusion of the exciting adventure saga entitled:
"THE FOUR POETIC CLUES MYSTERY, detectives Sam Hames, Howie Newbald and Ginny Hames sat smiling at their office conference table. They had a feeling of confidence they were ready for their next challenge.
As they discussed their future as detectives, Sam became serious. He stood up and announced:
"Recently I discovered a large, soiled, envelope, yellowed with age, in my father's World War One trunk or footlocker. After my father's recent death I became the owner of the footlocker and contents."
Looking at his partners with a serious demeanor he continued, "Inside, among many items, including his army uniform, I discovered this soiled envelope stuck to the lower inside wall. Inside this envelope I found these three old, large, skeleton keys." He tossed the three keys on the table top.
Sam hesitated, then suggested, "These Three Skeleton Keys could be the focus of our next adventure;
What secret objects, closed containers, doors or unknown places could these keys open?"
Do detectives Sam, Howie and Ginny need to investigate and discover the answers to these intriguing questions? Follow along, engage and participate in this drama as dangerous and exciting events unfold.