What could be more essential to us than water? It quenches our thirst, supports our agriculture, transports our products and as ice, it cools our gin and tonics. And as much as humans are stardust, we are also very much water babies, with up to a third of our bodies made up of water alone. Water is a mighty agent for physical change. Water can dissolve mountains, carve out canyons and wash away cities. And the absence of water means death for all creatures. In this episode, we’ll follow a water molecule (called Tinkle) as it travels through the freshwater cycle. We’ll discuss droughts and floods, life on other planets, and we’ll journey across frozen lakes and up huge glaciers. But most of all, we’ll find out why water is simple, crucial – and beautiful.