I had hoped for a more murder mystery movie. This was like here's the murderer and you saw everything around them. There was a plot twist at the end though, but that wasn't well executed.
The actors did a fairly good job.

But let's get on to the plot holes.
Weren't the married couple (Misaki and Sohei) reliable for anything at all. They hid the body for a few days and was trying to rewrite the will. Misaki should be arrested for attempted murder or at least assault for the pool and the same for Sohei for the attempt on the caretaker/maid at the stairs. She must have remembered that incident or her walking in on the dead body.

The more I wrote the lower the stars got. I thought of giving it a 6 in the beginning, but now it's a 5.