I would have seen this somewhere between the mid and late 1980s on TV, but I’m pretty sure it was a movie, and it was in color. I believe there was a big house or mansion, and I seem to remember two kids, a boy and a girl I think, wondering what was behind a locked door. There was a lady who basically wouldn’t let them see, and when the kids went away, she unlocked the door and opened it, to show the viewer that there was a guy tied up on the floor. I think he was conscious, and may have been gagged. I think she was making sure he was still in there, and she didn’t let him out. She may have used a skeleton key, and I’m inclined to think that the movie was set in an older time like the Victorian Era, possibly earlier. That is an assumption on the type of clothes I seem to remember them wearing. That’s all I seem to remember.