Hannah and Dan's high-maintenance mother Marion is to undergo an operation and Hannah is tasked with looking after her during her convalescence. Which basically means enduring Marion's constant requests for gin and tonic, hanging out at parties with her obnoxious friends and generally being made to feel inferior.
At the insistence of his mother and sister, Dan has finally booked himself in for an appointment at the STI clinic. There, under examination, he meets the funny and free-spirited doctor Izzy, who he immediately falls head over heels for. He plucks up the courage to ask her on a date and the romance begins. Slowly but surely Hannah and Marion start to find common ground, whilst Dan must shake off his straight-laced attitude to sex and prove to Izzy that he is definitely not vanilla.