In July 1405, the Ming Emperor Yongle gave Zheng He command of the greatest armada the world has ever seen. His brief was to travel to the Western Ocean with some 300 ships and persuade the rulers of far flung lands to pay homage to the Emperor as the "Son of Heaven". There has been much debate as to the size of these treasure ships, and this film investigates the truth behind the claims. Between 1405 and 1433, Zheng He led seven vast expeditions to kingdoms as far afield as India, the Middle East and Africa, covering 25,000 miles of ocean. It is believed that a few years after his death, Chinese officials destroyed all records of the treasure ship voyages, and China was to then turn its back on the outside world. Now, six centuries later, the truth about Zheng He's story is being pieced together from what few scraps of evidence still remain. Who was this extraordinary man who led an armada half way around the world decades before Columbus was to set sail for the Americas?