When a group of teenagers receive an invite to download the latest smartphone app, an intelligent personal assistant, they expect a harmless way to get directions and restaurant recommendations. But the sinister nature of the app soon reveals itself, tormenting the friends by tapping into their darkest fears.

A socially awkward teenager is blindsided when her mother introduces her to her new fiancée. At first, his charm, intelligence, and beauty seem too good to be true, and after a series of strange occurrences, the teenage daughter realizes that this new member of their family is not exactly who he seems.