This is another film that is completely silly and implausible.
Why would a loving father, a psychiatrist no less, subject his two newly grieving children to staying alone with his girlfriend (who is also on his books - there are guidelines around this abuse of power) in a completely isolated spot when they had never even met before?
Why would ANY father insist on this only six months after they had lost their mother in an especially traumatic manner?
Finally, I find it extremely dissapointing that, yet again, psychiatric illness is being used to drive a horror plot. I thought we had moved beyond that in Western society.
Apparently not so. I call it lazy.