In Regency England, an exotically dressed woman is found in the fields, speaking a language no-one can understand.

Mr Gutch, a local printer and newspaper reporter, takes an interest in the case, especially after the woman claims via mime to be Princess Caraboo.

When the Worralls leave on a trip the servants inspect her for a tattoo, which they believe all natives of the South Seas have and are shocked to find Princess Caraboo has one on her thigh.

Mr Worrall uses her presence to recruit investors for the spice trade which will be facilitated by her when she returns to her native land.

Gutch brings in Professor Wilkinson, a linguist who is initially dismissive of Caraboo's story but has enough doubt to refuse to say she is a fraud.