Don't think for a moment that because this has William Powell in it that it is going to be good.
I think what annoyed me the most about this mystery was that there was no real investigation. Powell's character would walk into a room and instantly know just where the clues would be. If there had been a hidden safe, he would have instantly found it.
I don't mind having a character who is a little more on top of things than the others in mysteries, but it's not so fun when it appears that they have already read the script and just have to hurry through the motions to make the mystery solving look official.