The Neighbour follows Mike, a middle-aged man in a routine marriage, wrestling with the fact that he feels his life to be passing him by. Yet, when a young couple moves in next door, Mike quickly befriends the young and vulnerable Jenna - herself trapped in a tumultuous marriage to Scott, a car salesman with an immature and pejorative streak. As Mike witnesses the perceived abuse of Jenna at the hands of Scott increasing, he makes one last drastic and misguided effort to intervene - and in the end only serves to completely sever his relationship with Jenna, his family and his life in general.