Dr Adam Bloom seems to have the perfect life. He is financially secure and lives in a luxurious house with his wife, Dana, and their daughter, Marissa, a recent college graduate.

Late one night, his daughter wakes him up and says 'Somebody's downstairs.' From that moment on, life in the Bloom household will never be the same.

As the family recovers from the break-in and the Blooms' marriage starts to fall apart, Marissa meets a young, talented artist named Xan. Adam feels that something's not quite right with Xan, but his daughter ignores his warnings and falls deeply in love.

When suspicious things start happening to the Blooms all over again, Adam realizes that his first instinct about Xan was probably dead on...