A stay-at-home securities trader, Mike Foster, has grown accustomed to his secluded life with his family. But his reality is soon disrupted after a failed kidnapping attempt on his wife and children. Feeling helpless and unguarded, Mike meets with his home's high tech developer who decides to install an android patrol guard, named Dell, to keep watch on the property.

Growing attached to the property itself, Dell begins to question Mike's ownership and authority while showing signs of hostility. After a power surge disables the home's security, Dell believes that Mike and his family are a threat to the house itself and attempts to eradicate them by any lethal means necessary.