The moon is such a familiar presence in the sky that most of us take it for granted. But what if it wasn't where it is now? How would that affect life on earth? Space scientist and lunar fanatic Dr Maggie Aderin-Pocock explores our intimate relationship with the moon. Besides orchestrating the tides, the moon dictates the length of a day, the rhythm of the seasons and the very stability of our planet. Yet the moon is always on the move. In the past it was closer to the Earth and in the future it will be farther away. That it is now perfectly placed to sustain life is pure luck, a cosmic coincidence. Using computer graphics to summon up great tides and set the Earth spinning on its side, Aderin-Pocock implores us to look at the moon afresh: to see it not as an inert rock, but as a key player in the story of our planet, past, present and future.