It's Christmas, there're presents and decorations to sort, a mouse to catch, and Sid Jones's daughter Sally is heavily pregnant.

Laid up in her parents' home whilst her husband Dennis is serving in the Far East, the baby is due any day, and when she eventually goes into labour, Sid and his best friend - next-door neighbour Willy - have a few drinks to celebrate.

The arrival of Sally's no-nonsense in-laws quickly complicates matters.