On a rainy London night in 1946, novelist Maurice Bendrix has a chance meeting with Henry Miles, husband of his ex-mistress Sarah, who abruptly ended their affair two years before. Bendrix's obsession with Sarah is rekindled; he succumbs to his own jealousy and arranges to have her followed.

On a dark, rainy night, a girl drives home and picks up an elderly woman who seems to be in trouble. She begins to doubt her good deed when something about her traveling companion begins to seem strange to her.

Clive (Kevin McNally) and Carol Smith (Rebecca Lacey) are a Merseyside couple who are struggling to raise their two teenage children, Wayne (Scott Neal) and Debbie (Heather Jones)