Earnest Callenbach's Ecotopia is a small country made up of what used to be Washington, Oregon, and Northern California. The story takes place in 1999, which is twenty-five years after it was written, in 1974. In the story, Ecotopia has been an independent nation for nineteen years, and most Americans, including the United States government, still do not know much of anything about their northwestern neighbor. The Ecotopians are secretive and cut off from their American counterparts and this has bred hostility from many on both sides of the border. The Times-Post of New York, with the approval of the president of the United States, sends William Weston, an internal affairs reporter, to Ecotopia to write a story explaining what is going on in Ecotopia. This book is structured as a collection of reports sent to the Times-Post for his story and entries from his personal diary.

When Weston sets out for Ecotopia, he talks to some Americans about their opinions of Ecotopia. Everyone he talks to expresses either a fear or mistrust, or both feelings towards the Ecotopians. One even goes so far as to tell Weston that they are all cannibals, and that Weston is dooming himself to be someone's dinner by going to Ecotopia! Upon crossing the Ecotopian border, Weston finds that the Ecotopians do not exactly hold a very high opinion of Americans either. Ecotopians feel that the people of the United States are all wasteful, barbaric, and prejudiced.

Over the course of six weeks, Weston come learns many things about Ecotopia, some of which are amazing while others are downright ridiculous. He makes several friends who lead him on an interesting and enlightening cultural adventure. He gets involved with a woman named Marissa Brightcloud, and over the course of his stay in Ecotopia, falls in love with her.

As the assignment draws to a close and his time to return to New York approaches, Weston begins to realize that he has changed. He begins to see himself more as an Ecotopian than an American and sees life from the same perspective. As he reads over his columns, and looks back at his life, he realizes just how much he really has changed, as well as how much he loves both Marissa and Ecotopia. As the story draws to a close, Weston decides that he will stay in Ecotopia with Marissa. He sends his boss in New York his last column, his journal, and a note explaining his decision.