Housebound after a stroke, elderly Betty Wallis receives her basic needs through visiting caregivers, who visit briefly each morning and night. Soon however, Betty finds she is not alone, as an intruder inhabits her home.
Unable to speak and with the invader eluding detection, Betty finds herself stuck in a frightening situation as the figure begins to move in permanently. After sleepless nights, she is finally confronted. A teenage runaway, Grace, has become brazen enough to move about the home freely. Realizing she is unable to call for help, Betty launches her offensive as best she can.
Undeterred by her efforts, Grace continues to live with Betty and avoid the caregivers, raiding the fridge and occasionally taking a shower. Although frustrated, Betty begins to find comfort knowing Grace is there. Their relationship grows to one of mutual respect and finally into friendship.