Meet Rosemary, 86, and Kate, 26: dreamers, campaigners, outdoor swimmers...
Rosemary has lived in Brixton all her life. But now everything she knows is changing - the library where she used to work has closed, the family fruit and veg shop has become a trendy bar, and her beloved husband George is gone.
Kate has just moved and feels alone in a city that is too big for her. She's at the bottom rung of her career as a journalist on a local paper, and is determined to make something of it.
So when the local lido is threatened with closure, Kate knows this story could be her chance to shine. And Rosemary knows it is the end of everything for her.
Together they are determined to make a stand, to show that the pool is more than just a place to swim - it is the heart of the community. Together they will show the importance of friendship, the value of community, and how ordinary people can protect the things they love.