Will, Penny, Smith, the robot, and their new traveling companion Willoughby (described here as 'a purple kangaroo') have taken shelter from a storm in a cave, where Penny reads aloud from a tattered copy of 'The Collected Works of Lewis Carroll'. Willoughby is fascinated by 'The Hunting of the Snark', and dismayed when Penny is unable to finish the poem due to a missing page ("I simply must know how it ends!"). He offers to recreate the lost page through the use of 'ESQ', "a mental process at which I am somewhat adept", but his efforts go awry and the group find themselves transported into the fictitious universe contained within the book, "a dimension where fantasy is real and what is real is fantastic...a most curious place". "It all seems frightfully psychedelic", notes Willoughby. Smith and the Robinsons are startled to find that the familiar characters who inhabit this world are all strange mirror-images of themselves, and when Willoughby's efforts to ESQ them back to reality fail, they soon find themselves at the mercy of the deranged Queen of Hearts, who is the spitting image of Dr. Smith...
It's been confirmed by both Joel Eisner and Mark Phillips that during the production of the show's third season, Irwin Allen wanted to add a new character, a talking animal named Willoughby. MALICE IN WONDERSPACE seems to be one of only two scripts prepared in anticipation of this proposed change to the series' format, and it offers an interesting glimpse of what a fourth season might have been like. If the plan was to have Willoughby inadvertently stir up new kinds of mischief each week through the use of mental powers that are indistinguishable from magic, it probably would have been an awful lot like BEWITCHED. I'm not convinced this would have been a viable long-term survival strategy for the show, but Wilber's script at least is not without certain absurd and surreal charms.
Apparently several animals were under consideration, and Wilber's script suggests a final decision hadn't been made at the time he wrote it. Willoughby is initially identified as a kangaroo, but later described as a 'quadruped intelligence from the planet Arka'.
Another curious aspect of the script is that the characters John, Judy, and Don don't appear at all, not even in the kind of thankless cameos that Guy Williams, Marta Kristen, and Mark Goddard must have been resigned to by this point in the series, though June Lockhart would have turned up briefly in a hallucination scene (her only line: "Thank you, young man.") There are no scenes set at the Jupiter 2 campsite, either. These omissions result in a story that feels strangely detached from the regular dynamics of the show, though it's possible that subsequent drafts would have integrated some of the missing elements.
Copies of the script are easy to find on the collector's market, and anyone who's a fan of all three seasons of the show will probably enjoy reading it.