Hetty Waintthropp is annoyed at the cards celebrating her sixtieth birthday - they all offer her well wishes for "joining the club" of senior citizens and old-age pensioners, even though she's not entitled to a pension. Determined to make something of herself, Hetty gets a job at the local post office, where she proves her mettle quite quickly by throwing out a troublemaking biker and chasing down a shoplifter.