Oliver and his wife arrive by Eurostar to attend the birthday party of grandchild Hugo. Hugo's grandmother Harriet is also on her way. Oliver and Harriet fail to recognise one another at first - but the physical attraction is instantaneous. Harriet's son, Roderick,, a successful banker, is married to Jennifer, who works in publishing.
Attempting to reconcile careers, marriage and children leads to high stress levels as the two generations walk a dangerous tightrope between fidelity and parenthood.