This combines several elements of previously filmed ideas. The evil creature/force/spirit inhabiting the bodies of humans to wreak murderous havoc dates back at least to the 1967 Star Trek episode "Wolf in the Fold" (#2-14) and recurs in the 1998 movie "Fallen". Also borrowed from both is the notion that the evil being can move from body to body but, in an added little touch from "Fallen" has only a small amount of time to find a new host or die.
However, the ending of this particular story involves a nice little twist that both of its predecessors missed, an ending which will remain undisclosed here but makes this story still worth watching even if you've seen both its forebears.
However, the ending of this particular story involves a nice little twist that both of its predecessors missed, an ending which will remain undisclosed here but makes this story still worth watching even if you've seen both its forebears.