S1·E26 Swan Song

The final episode of the series begins with an adulterous consummation, and ends in death. Jon succumbs to Fleur's seduction and immediately regrets his infidelity to his wife, Ann. It's apparent that Fleur will never give up, so Irene intercepts her at June's studio. Giving her a look at what the future will hold, she then drops a bombshell: Ann is pregnant with Jon's child. Soames advises a distraught Michael to stay the course, while Fleur must face the loss of Jon forever. A fire in Soames's picture gallery causes him a fatal injury, and as Fleur and Michael gingerly reconcile, Soames takes his final breath.