Kathryn is a cool cucumber and eventually makes Dumarest a deal he can’t refuse: free her daughter’s mind from the Tau, an alien virtual reality device, (where it has been trapped for years) and gain his freedom, or suffer death by impaling.   Dumarest learns all he can about previous failed attempts (all of which have resulted in the rescuers dying or being reduced to vegetables) and goes in.  Iduna, Kathryn’s daughter, is a virtual goddess within the Tau and forces Earl to play games, some romantic and some violent. 

Dumarest’s preparations have led him to believe that Iduna survived because she was a child drawn by curiosity when she entered the Tau and her sense of fantasy and imagination allowed her to accept and master what she found.  Her would-be rescuers went in with a grim outlook expecting nightmarish horrors, and found exactly what they expected.  In spades.  Dumarest tried to enter the Tau with the same curiousity and positive frame of reference as the child, and although this eventually saves him, he has a few fairly nightmarish encounters himself, before he finally gets a grip.  As he learns how to manipulate the reality of the Tau himself, Earl relives moments from his childhood and receives advice from people he has known (including the captain of the ship on which he originally left Earth as a child, and Jocelyn, the whimsical Lord of Jest from Book 5, The Jester at Scar) as constructs formed from his subconscious mind.

Dumarest finally realizes that although he might eventually become as good or better than Iduna at manipulating the Tau’s reality, he will never be able to convince her to leave.  Dumarest has a moment of hesitation himself, upon realizing that within the Tau he could find Earth and live there with Kalin, so to Iduna the constant adventures and companions her still-childish imagination can create must seem infinitely better than her highly structured, disciplinarian upbringing as heir to Esslin’s throne.  Dumarest also realizes that while Kathryn will keep Iduna’s real-world body alive forever, she won’t wait that long for him.  He rather crudely rejects Iduna’s romantic interest and provokes her into a lethal game, and she unveils her new Champion and Dumarest’s opponent in a fight to the death: himself!  Iduna hasn’t seen all of Dumarest’s tricks, however, and the simulacrum is losing the fight until Iduna cheats and conjures up a winged, fanged monstrosity as an ally for her champion.  Earl's avatar is killed, and he wakes up in his real body (just in the nick of time, as Kathryn was about to let her scientists perform electroshock and other horrible experiments on his apparently comatose body to see if they could stimulate him somehow).

Dumarest explains the situation as gently as he can, and Kathryn (who is pretty sharp) fills in the blanks, understanding why her daughter prefers being a virtual goddess to a real princess.  Dumarest also reveals a plot against the royal family he has unraveled from clues gained both in the real world and from Iduna in the Tau.  The original acquisition of the Tau by Gustav, Kathryn’s consort and a collector of antiquities and curiosities, was plotted by Tamiras (a main character in an otherwise unrelated sub-plot involving Kathryn and the planet’s economy that takes place while Duamrest is in the Tau). Tamiras’ mother was killed years ago in an abortive coup attempt against Kathryn, and he sought revenge by tricking Kathryn’s only daughter into the Tau.

Although Dumarest has failed to rescue Iduna, he has shed more light on her condition than Kathryn’s scientists and previous would-be rescuers have managed, as well as exposed a traitor, and Kathryn grants his freedom (and a reward sufficient to buy passage off-world).  An optimist might believe Kathryn now has enough information about Iduna’s condition and the internal workings of the Tau to eventually make a successful rescue.  Dumarest, however, believes it’s only a matter of time before Kathryn joins her daughter permanently in the Tau (and leaves a leaderless planet to the mercy of bickering noblewomen eager to feud over the remnants of Kathryn’s regime).  And, given Dumarest’s long, unpleasant history with slavers, he doesn’t really care.