Sam and Lucy Bell (Hugh Laurie, Joely Richardson) are bright, thirtysomething media darlings - he's a TV Commissioning Editor for the BBC, she works in a theatrical agency - who seem to have the perfect life. More than anything, Sam and Lucy want a baby, and so they embark on a rigorous schedule of lovemaking dictated by ovulation charts rather than passion. Nothing appears to work. In desperation, they deliver themselves into the hands of Dr. James (Rowan Atkinson), who suggests the possibility of IVF as the way forward.

The endless medical tests soon take their toll on the couple's relationship. Sam vents his frustration by penning a screenplay based on his current predicament: a comedy about a couple trying for a baby. Meanwhile, Lucy's hormones are all over the shop and she finds herself increasingly attracted to the star client at her agency, suave and debonair actor Carl Phipps (James Purefoy).