Lonely and abandoned by her abusive husband, Mary is quick to accept the friendship of widow Ruby after saving her life during an apparent seizure on the New York subway. The older woman embraces Mary, urging her from her reclusive existence and back into life again. When Ruby rescues her after Mary's husband returns, her trust seems vindicated. But after Mary jokingly says she wishes he were dead, his body washes up in the East River, showing signs that his death was no accident. Red flags begin to pop up, leaving Mary to wonder who Ruby really is. She escaped from her husband in the past, but can Mary survive her new best friend?