France, late 50's. The family's daughter and her husband (supposedly still student) are still living with dad and mom, and they give birth to seven children, and the eighth is expected soon. Dad is sick and tired of this fertility till... A childhood industries rep turns up and tells him that, if he can have 12 grandchildren before he turns 50, he will be the winner of a hefty sum: enough to buy a country house, every Parisian's wildest dream. But the hubby's fertility seems to run dry at the very moment when his in-law urges him to be prolific again.