Missing pieces (3)

When they reached the place, they found an empty spot so they started looking around. After some time Kevin thought of something and touched the empty air in front of him and as he expected it was not air, there was a hard wall in front of him "Do you are smart, Robert." he commented to himself. He then ordered all the people who came with him to find the entrance by touching the walls.

Just when they found out where the entrance was and were about to enter, Robert blocked his way and pushed him a little "Do you really think I will let you into my house that easily when I was successful keeping you out for so many years. Mark my words, I won't let you harm her or use her for your evil plans."