For millennia the planets have fascinated mankind. But only in the last 40 years have those wandering points of light in the night sky been revealed in all their glory, unmasked by a fleet of satellites and interplanetary probes. And the closer we look, the more wonderful they are. "The Planets" follows the tracks of robotic rovers over Mars, plunges through Titan's atmosphere on the back of the Hugyens probe, smashes into a comet with Deep Impact, and discovers the frozen planets that lurk at the edge of our solar system, beyond the orbit of Neptune