It is set mainly in Manaus, Brazil, early in the 20th century and conveys the author's vision of the Amazon River.
Anne Fine, British Children's Laureate (2001-3) and one of three former winners on the Guardian panel, wrote that "we all fell on Eva Ibbotson's perfectly judged, brilliantly light to read, civilised Journey To The River Sea, in which we are shown how, as one of the characters Miss Minton reminds us, 'Children must lead big lives... if it is in them to do so.
Maia, an orphan, is sent from this safe and cosy environment to stay with distant relations, the Carters, who are not as kind as she had hoped for.
Beatrice and Gwendolyn, the twin daughters, are selfish and seem to be brought up strictly to be British, while their father, the eccentric Mr Carter, obsessively collects the glass eyes of famous people.
The family plans to see a play starring Clovis King, an English child actor, but the twins lie and say that all the tickets had sold out so they couldn't buy one for Maia.
When Maia finally gets to watch Little Lord Fauntleroy, Clovis acts very well, but during the pivotal scene, his voice cracks and the play is ruined.
Mrs. Carter, distracted by Beatrice and Gwendolyn's fighting, accidentally spills insect repellent onto the oil lamp, burning the twins' bedroom and finally the whole house.
One day, Maia is singing for the Xanti when the police from Manaus hear her voice and also find Miss Minton's corset, and, thinking they are rescuing Miss Minton, Maia, and the curator of the Natural History Museum, take them back to Manaus.
In the end, Mrs. Carter, Beatrice, and Gwendolyn return to England to become servants of their wealthy relative, Lady Parsons.
She used to live and study in a boarding school in England, called "Mayfair Academy for Young Ladies"; all fees were subsidized by her parents' trust fund.
She also forms remarkably close bonds with both Clovis King and Finn Taverner, who are, if in different ways, in lonely and vulnerable situations similar to her own.
Later, Clovis takes Finn's place as heir at Westwood in England, convincing detectives of the false identity.
Sir Aubrey sent the crows to find Finn, as he needed the son of Bernard Taverner to inherit Westwood.
He later had a son, Finn Taverner, and lived in Manaus with plenty of friends, such as the Indians, Professor Glastonberry, and many more people.
Mr Carter is a very mysterious man; he doesn't really care for his family and spends all day in his messy office obsessing over his collection of eyeballs.
She is introduced as a "tall, gaunt woman" wearing black clothing and frightening accessories such as a hatpin modelled after a Viking spear and a steel, beaked umbrella.
A close friend of Bernard Taverner, she is revealed to be the maid who helped him escape his abusive household and reach the Amazon when they were younger.
Miss Minton takes the job with the Carters in order to follow her late friend's journey to the Amazon.
She has a witty and dry sense of humour, and is cunning, using deception and acting in order to protect the children from unkind and corrupt individuals, such as the detectives.
Whilst being led astray from their mission by residents of Manaus and the Amazonian Natives (all of whom despise them, being friends of Bernard and Finn Taverner), they befall a series of comedic misfortunes.
Their racism towards the Natives is also their downfall, as they are mocked by the tribes, refuse to change out of British attire and therefore overheat, and are easily deceived by Finn's charade towards the end of the novel due to their irrational prejudices.
Sir Aubrey Taverner is an true Englishman who lost his son, Dudley, who died on a horseback accident as he broke his neck.
and wants Finn to return to England and take his place as the heir to Westwood, the Taverner family estate.