Summer in London stops for no-one. Not the half-naked boozers, stoners, and cruisers, the hen parties glugging from bejewelled bottles, the drag queens puffing on hurried fags. It's June 2019, and everyone has converged on the city's parks, beer gardens and street corners to revel in the collective joys of being alive. Everyone but Maggie. She's 30, pregnant and broke. Faced with moving back to the town she fought to escape, she's wondering if having a baby with boyfriend Ed will be the last spontaneous act of her life. Ed, meanwhile, is trying to run from his past with Maggie's best friend Phil and harbouring secret dreams of his own. Phil hates his office job and is living for the weekend, while falling for his housemate, Keith. But there's a problem: Keith has a boyfriend and there might not be room for three people in the relationship. Then there's Rosaleen, Phil's mother, who's tired of feeling like a side character in her own life. She's just been diagnosed with cancer and is travelling to London to tell Phil, if she can ever get hold of him. As Saturday night approaches, all their lives are set to change forever. It's the hottest summer on record and the weekend is about to begin...