Incoherent and illogical plot

Rating: 3/10 (13 May 2017)

*** Spoiler ***
The first half of the film is about black people that serve their "white families". They do all the time hard work, even at night. One appears to be there to satisfy an old lady. These black people appear to be under mind control. They are indeed manipulated by a very effective hypnosis.
The last third of the film switches the story line drastically. Suddenly we see how a brain is cut open for a supposed brain transfer to the new body.
* If large parts of the brain of the victim is removed, how can the personality of the victim come back just via flash? * If the grand parents are now in the new bodies, why are they treated like slaves?
I liked how the first part of the film built up tension, and was hitting hard on the hypnosis theme. I didn't like the last part, because it simply doesn't fit with the the rest of the film.