The young couple, Sarah and Blake, are initially excited to have a tenant, named Bob, living in their converted garage. However, they soon start to notice strange and unsettling behavior from Bob. He becomes overly involved in their personal lives, constantly invading their privacy and showing signs of obsession with Sarah.
As the couple begins to feel increasingly uncomfortable and unsafe in their own home, they discover that Bob has a dark and disturbing past. They become determined to find out the truth about their lodger and ultimately uncover a shocking revelation that puts their lives in danger.
The couple must now fight to protect themselves from the man in the guest house, as he becomes increasingly unhinged and dangerous. The movie builds tension as they try to outsmart Bob and escape from his clutches. Ultimately, they must face their fears and confront the man in the guest house in a thrilling and suspenseful climax.