Blackburn, Lancashire, 1919. The five-year-old Arthur watches as an unknown man enters his house and takes his place in his bed beside his mother. Who is this man he must now call 'Dad'? Will he be like Tom's dad, get drunk and beat up his mother? Arthur tries to help his father gain some self-respect when the mill workers strike and Billy finds himself out of work. In the process they both learn how to be true to themselves and each other.