The Mysterious Attic

There is a boy named Matthew and a girl named Caitlyn who are siblings. They get along very well. They always wonder what's in the attic in their home. When they try to sneak up into the attic their mother always catches them and tells them to stay out, to never go near the attic, but they don't listen. One day they hatch up a plan to sneak up into the attic at night while their mom's asleep and they're never heard from again.What could they have possibly found in that mysterious attic.