[1][2][3][4] Adventurer and gem expert Jean Baptiste Tavernier promises a diamond to cap King Louis XIV's crown for the coronation, but the reckless haste of the king's emissary, Baron Paul de Cabannes, causes the jewel to be cut badly and ruined.

Cabannes insists on coming along and complicates the journey more than once before saving Jean's life and earning his respect.

In the temple, Jean and Cabannes learn of the Eye of the Goddess, a rare blue diamond.

It is in the possession of the Mogul of Golconda, who promises to give it to Queen Maya as a wedding gift, but secretly plans to take rule of her country.

With the use of a new "secret weapon," a prototype of hand grenade, the Frenchmen are able to overcome the Mogul's men in battle.