A mysterious billionaire, Nathan, invites Caleb, a programmer who won a company lottery, to spend a week at his secluded mansion. The mansion, hidden in the woods, is actually a high-tech research facility. There, Caleb is introduced to an artificial intelligence robot named "Ava," and he soon discovers that the real purpose of his invitation is to conduct a "Turing test" on Ava, testing her artificial intelligence capabilities.