Xanth's King Trent has left for drear Mundania, leaving Dor to practice governing the magical kingdom of Xanth. Dor's magical talent is communication with the inanimate which for information gathering is very helpful, but for dealing with citizens needing discipline it leaves room for improvement. But when Trent goes to establish trade routes with Mundania, Dor and his friends (a golem named Grundy, the centaur Chet, Smash the ogre, and Dor's love interest Irene) must keep the land in line.
However, former King Trent does not return after the week he was supposed to. After three weeks, Dor gathers his gang and decides to go on a quest to help rescue Trent from what is surely a horrible fate of imprisonment in non-magic Mundania.

This mission leads them to Centaur Isle, to find an unknown Centaur Magician. Centaurs are very negative on the concept of having magical talents, so when they find Arnolde the Centaur and discover his talent, he is exiled and willing to help them rescue Trent. Arnolde's talent is a magical aisle, creating a field of magic around him that allows anyone to use magic in Mundania.

The whole gang (minus Chet) travel by rainbow north to Mundania. While in Mundania, they find a scholar named Ichabod. From him, they learn that they are in the wrong time strand and must go back to Xanth and re-cross the border. Eventually Dor and his friends find the correct time and go to the castle where they think Trent and his wife Iris were last. After a nice dinner and a little betrayal, they get captured and locked in a dungeon. After escaping, they smash down a couple walls to find Trent and his new friend King Omen, the proper king of this area.

The group (plus the new additions) struggle to get Omen into his rightful throne. After exchanging farewells, they decide to return to Xanth with King Trent and Queen Iris.