The ship on which the merchant's daughter Celia Lampri was traveling was captured by pirates. The girl was captured and sold into the harem of the Turkish Sultan. Celia's fiance, the English merchant Paul Pindar, has been looking for his beloved for four years. One day he learns about a tournament taking place in one of the best gambling houses in Venice. The prize is a diamond of incredible size and purity, rumored to have been stolen in Turkey from Safiye Sultan herself... The diamond thieves saw Celia in a harem, and Paul hopes that they know how to save her. Meanwhile, the sea throws up a barely alive woman with a difficult life on the Italian shore. as a baby. She is silent all the time, but the saviors, the inhabitants of a poor fishing village, take her for a real mermaid...