Once a slag, always a slag? It’s the 1990s. Sarah is 15, obsessed with boy bands, sex and getting drunk on Malibu.

Most of all, she’s hung up on her teacher, Mr Keaveney. Fast forward 26 years. Sarah is 41, the last of the party girls.

But the mad nights out are losing their shine. And her teenage dreams are now distant, queasy memories. There’s only one thing for it: an adventure.

So, Sarah sets off with her sister Juliette on a whisky-fuelled campervan trip across Scotland. The sisters have never been alike, but they know all the dark corners of each other’s history – and it’s time to dig up some demons, kicking and screaming. Because the things that once defined us shouldn’t define us forever, should they?