The Towers of Illica by Emily Rodda

Star of Deltora series bk. 3. Scholastic, 2016. ISBN 9781742990644
(Age: 9+) Highly recommended. Britta's dangerous journey continues as The Star of Deltora sails through dangerous waters, surrounded by a ghostly presence. This is the most important trade, her final opportunity to defeat the other contestants and win the Rosalyn Contest. Aboard the ship, Britta senses constant dangers, there are enemies on board who wish her harm, putting her life in danger, hiding key books that explain the secrets of Illica, how to trade and discover the wealth of the island. Her memories of playing with Captain Gripp's model ship as a child are extremely useful, as she hides her two Moons purchases in the cargo hold. After a fierce storm where Britta is pushed overboard and a daring rescue by Sky and Jewel, she realises that she does have friends on board.
The mysterious island of Illica is dominated by three towers, each of the contestants must stay a night with the secretive families who inhabit these towers and complete their final trades. Of course, all is not as it seems. After a bath in the bathhouse and a visit to Suli the Needle, Britta is appropriately dressed and nearly ready for the evening's adventures. However, when Jewel and Britta choose to follow Sky who mysteriously disappears into a cave in the cliffs, they are plunged once more into danger.
Britta is a strong female protagonist; she is brave, fearless, although a little foolhardy at times, she makes some decisions rashly and others thoughtfully. Rodda builds intrigue with plot twists, the ever present wraiths, hints of a new island - The Isle of Jade and glimpses of Britta's father's tortured existence on the Island of Tier. The Towers of Illica ends with more questions than answers, truly Britta's journey seems to be even more dangerous than before.
Rhyllis Bignell