Coworkers Ruby and Harry are in love - but they're married to other people. They decide to tell their spouses that their marriages are over and to start a new life together. Ruby has wanted to leave her controlling husband for a while, so she tells him she's leaving and waits at the hotel where she and Harry are to meet. But Harry never shows up.
Suddenly, Ruby has lost everything. Harry won't answer her calls, and she's fired from her job. She finds a cheap apartment in a run-down part of town, all the while wondering what happened to Harry.
Just as Ruby thinks she's hit rock bottom, strange and menacing things start to happen - someone is sneaking into her apartment, and someone is following her home late at night - and she is going to have to fight for her survival.