Out of the four rocky planets of the inner Solar System, Mercury is the one least explored. Hot and more difficult for an orbiter to reach than Saturn, the planet long eluded scientists. With its two probes, BepiColombo will be the second mission ever to orbit Mercury and the most complex one. Packed with scientific instruments, it will try to answer many perplexing questions: Why is there ice in the polar craters of the scorched planet? Why does Mercury have a magnetic field? And what are the mysterious 'hollows' on its surface? Learning more about Mercury will shed light on the history of the entire Solar System.