Kate has spent the last 18 years lying motionless in the bedroom of her parents’ house surrounded by objects from her youth. Miraculously, she awakens - but her mind and spirit are stuck in 1988. Her parents and friends are awestruck but Kate is bewildered by what has happened. She tracks down her boyfriend Pete, who has a new girlfriend and a new life. It is only by meeting him that the painful reality sinks in. Her mother and father throw a party for her to celebrate her birthday and Kate declares she is hell-bent on catching up on lost time. But she starts to have flashbacks to the birthday party 18 years before. Who was the teenager who died and why was Kate injured?
Kate is fearful that she might have killed Brian herself on that fateful night 18 years ago. In an attempt to catch up on lost time, she moves out of her family home and in with Sally, but it turns out to be an unsettling experience. Meanwhile, her parents decide to go on holiday to celebrate their wedding anniversary. But while Toby and Eileen are waiting on the platform, the same old arguments arise and they never leave the country. Pete proposes to his girlfriend Emma, and she accepts. At their engagement party, Kate ends up snogging Sally’s ex-fling, Matt. Ultimately Kate realises that she can no longer live with Sally.
The world that Kate left 18 years ago is far different now and she hates many aspects of it. She decides to start fundraising for the human rights group that Pete’s fiancee, Emma, works for. Amanda’s young son Dexter helps out and a sexual chemistry develops between Kate and Dexter. One thing must surely lead to another. Meanwhile Joe and Esther are still trying for a child, but he has started questioning his own sexuality. Later on a mysterious character turns up who seems to know Kate and her friends.
Kate decides to get away from it all by going on a trip. A travel agent friend suggests she go get photos for her new passport while he makes up a list of possible destinations for her. She goes outside and steps into a photobooth, but as the flashes go off, she flashes back to that fateful night.