Gasman (1998)

It's the Christmas season. With her mum's help, Lynne, a girl of perhaps eight, dresses up; her younger brother Steven plays with a toy car. The children leave with their dad, who's affectionate towards them. They walk down a railroad track where an unkempt woman waits with two children, about the same age as Lynne and Steven. The children go with them. They're all headed to a holiday party at a pub. Lynne notices that the girl acts a little too familiar with her dad. What's going on?