Bristol, England, early 19th century. A beautiful young stranger who speaks a weird language is tried for the crime of begging. But when a man claims that he can translate her dialect, it is understood that the woman is a princess from a far away land. She is then welcomed by a family of haughty aristocrats that only wants to heighten their prestige. However, the local reporter is not at all convinced she is what she claims to be and investigates. Is Caraboo really a princess?

Based on the true story of Mary Willcocks Baker, who appeared in 1817 in Gloucestershire, England, speaking an unknown language and behaving strangely. Through signs and gestures she claimed to be a princess from an island called Javasu, who had been kidnapped by pirates and escaped. For several months, "Princess Caraboo" was a national figure and was welcomed into high society. Her story was revealed as a hoax after a local woman saw her face in the newspaper and recognized her as a former tenant. After being exposed, the real Mary Baker faded into obscurity and died in 1864 at the age of 75.