Meet Rosemary, 86, and Kate, 26: dreamers, campaigners, outdoor swimmers...Rosemary has lived in Brixton all her life, but everything she knows is changing. Only the local lido, where she swims every day, remains a constant reminder of the past and her beloved husband George. Kate has just moved and feels adrift in a city that is too big for her. She's on the bottom rung of her career as a local journalist, and is determined to make something of it. So when the lido is threatened with closure, Kate knows this story could be her chance to shine. But for Rosemary, it could be the end of everything. Together they are determined to make a stand, and to prove that the pool is more than just a place to swim - it is the heart of the community.