The Simkins family was more or less normal mother, father, two teenage children until the father met an attractive American. Then came divorce, followed by the errant father being the beneficiary of a remarkable stroke of luck.
As a result, the Simkins tribe grew to include mother's new boyfriend, the son's surprisingly pretty girlfriend, the father's singular American girlfriend and, eventually, the daughter's realisation of a dream a top-class footballer boyfriend.
But it's not a smooth ride. The involvement of lawyers who exhibit the most staggering incompetence serves only to muddy the waters, the unwitting gathering of the whole greater Simkins clan at the run-down establishment of a gay hotelier leads to the appearance of a racist, homophobic policeman in charge of the Riot Squad and the father very nearly achieves notoriety when, as a result of achieving a state somewhere way the other side of drunkenness, he tries to seduce his own daughter.
Add in the commentary provided by the family dog (!) and what results is a joyous tale that moves from domestic normality at the outset to chaotic hilarity at the end.