Free Up In A Heaval by Piers Anthony

he agreed, salvaging what he could of this as he donned the knapsack. “Where is she?”
    Sammy launched out of his nap and headed for the horizon.
    “Castle Roogna,” Breanna said. “That way.” She pointed after the cat.
    “Wait for us!” he cried, running after Sammy. But he was already far behind. How had Jenny Elf ever managed to keep up with this feline?
    Sesame slithered beside him, traveling far more readily through the mixed brush. She gave him a look and a nod.
    Taking the hint, he emulated a light serpent rider and jumped on her back. His hands clung to her sleek scales, and she formed a niche to hold him in place. Then, sniffing the scent of the disappeared cat, she slithered on at a swift rate.
    “Thanks!” he gasped.
    They slithered rapidly through glade and forest, o'er hill and dale, and across a river or two. It all went by so rapidly he hardly had time to assimilate it.
    Until they came to a third river. There was something swimming in it that Sesame didn't understand, so she stopped at the bank. She could scare back sharks or allegations, but it wasn't smart to swim with an unknown menace.
    But it turned out to be a boy. He spied them and waded out. He had gills on his neck and fins on his arms and legs, but these faded as he came ashore. “My name's Kiel,” he said. “I have the talent of adaptation. When I want to swim, I grow gills and fins; when I want to fly, I grow wings.”
    “I'm Umlaut, with the talent of emulation. But I can't take it nearly as far as you can. I just halfway look the part; I'm not real. It is similar with Sesame here.”
    “Too bad,” Kiel said. He dived back into the water, forming gills again as he did.
    They concluded that the water must be safe and swam across. Umlaut was a bit jealous of those who had more substantial talents than he did, but he didn't want to say so.
    Soon a fancy castle hove into view. This was surely Castle Roogna, famed residence of King Dor and Queen Irene. Umlaut wondered whether there would be three challenges to get into it, but that turned out not to be the case.
    Sammy ran right past the snoozing moat monster and into the castle, and Sesame slithered after him. Three little girls appeared, looking to be about six years old. One had a nice green dress, another a brown dress, and the third a red dress, and their hair seemed to match. All three wore cute little crowns.
    Sammy tried to run past them, followed closely by Umlaut and Sesame, but one hummed a melody, the second played a harmonica, and the third beat on a little drum. Suddenly a magic web held the three visitors in stasis. This was strong magic.
    “Who are you?” the first asked. Then she answered her own question. “Sammy Cat!”
    Everybody knew Sammy!
    The magic eased, turning them loose. “And I'm Umlaut, and this is Sesame Serpent,” Umlaut said, completing the introduction. “We're looking for Princess Ida.”
    “We're the three princesses, Melody, Harmony, and Rhythm,” the second child said.
    “You don't want to eat Aunt Ida, do you?” the third asked, looking at Sesame.
    “We just want to give her a letter,” Umlaut said quickly. “And visit Zombie World.”
    “Oh, that's all right,” the first princess said. Umlaut thought she must be Melody, because they seemed to speak in turns, as she was the first to have spoken and the first one named.
    “She's nice,” the one who must be Harmony said.
    “Next door down,” the one who must be Rhythm said. Sammy took off again.
    “Thank you, Princesses,” Umlaut said, hurrying after the cat.
    The princesses faded out, literally. Umlaut was sure they weren't demons, but they evidently had some magic tricks.
    The door opened as they reached it. A sensible-seeming adult woman stood there. She wore a conservative crown too. A tiny sphere revolved around her head. “Princess Ida?” Umlaut inquired somewhat breathlessly.
    “Indeed,” the woman agreed.
    “We—”
    “The princesses told me,” Ida said. “Do