Jacob (Domhnall Gleeson of ABOUT TIME) is a worker at a computer company who wins the company lottery and gets to stay with the CEO at his secluded cabin in the mountains for a week. It's presumably a great honor. The owner, Nathan, is very strange and temperamental. He reveals to Jacob that he's invented an artificially intelligent being, Ava, and he wants Jacob to test her to see if she can truly think for herself. He quickly begins to think that she can--and he even begins falling in love with this seemingly innocent being.
This is one of those movies that start off as one thing and then turns into something different, which works really well here. The movie is creepy and unsettling. Recommended.