The Voyage of the Dawn Treader

The 3rd published book in “The Chronicles of Narnia”, but is the 5th (of 7) chronologically.

The story begins with Edmund and Lucy Pevensie staying for a time with some of their relatives; including, to their displeasure, their cousin Eustice Scrubb. Then, amidst a trying conversation, Eustice is portaled with Edmund and Lucy into the world of Narnia. Unfortunately for them, they fall into the ocean upon arrival.