Jon sat there in the tub, waiting impatiently for her mother to bring her the stone. She almost considered trying to get it herself again, but her tail was still smarting from her previous attempt. Moving around on land would be tricky enough on a smooth surface like the bathroom tile, but the rough carpet in the hall was sheer hell. It would be much less painful to just wait.
And so Jon waited. There wasn't much else she could do, except count the tiles. This being the kids' bathroom, there weren't even the Popular Science magazines that Jon's dad kept in the master bath. She couldn't think of anything interesting to think about, and the last thing she wanted to do right now was inspect her new body, so she just ended up staring at the ceiling.
Jon was so bored that she almost didn't notice that she had to go to the bathroom. Groaning inwardly, she worked her way out of the tub and onto the floor. She had hoped to get through this without getting acquainted with her new parts, but going in the tub would be far less pleasant. She managed to get astride the toilet; the flexibility of her new tail helped in contorting herself so that her frontal slit was facing down into the bowl, but when she prepared to release, the slit failed to open. Clamping up again, she gingerly pried open her frontal slit.
She got a disconcertingly good look at her new genitals, but there didn't seem to be a urethra anywhere in there. Come to think of it, the telltale "pressure" feeling was centered further back than usual. Hoping her hunch was correct, Jon twisted herself around into a sitting position and released, her back slit opening up for the purpose. From there, everything worked about the same as before, which Jon found comforting. At least she could maintain a sitting posture for the task, instead of having to straddle the toilet like she had thought. She idly wondered whether mermen's penises were still used for urination, or whether they also had the urethra in the back, then nearly gagged when she realized she'd been thinking about mermen's penises.
Jon wiped and clambered back into the tub, trying not to notice the way her breasts bounced and jiggled, thankful that that hadn't been any more complicated than it was. Finally, her mother came back in, looking a little exasperated. "Sorry it took so long," she said. "I had a bit of a knock-down drag-out with Mikey; all we had that would fit her were Zoe's old doll clothes, and she was bound and determined to not wear dresses or skirts, but I wasn't about to let her go to school naked. I eventually had to pin her with one hand while I slipped the skirt on with the other. I do hope she adjusts better than this in the long run. Anyway, the disabilities coordinator called back, and we've got a $100,000 grant to build a house for you, plus whatever it takes to dig a connection to one of the water tunnels going to the ocean. Your father's researching mermaid-oriented housing designs, and he'll get a rough draft of the blueprints together. As if I needed another reason to be glad I married an engineer."
"The stone, Mom?" Jon queried, getting impatient.
"Ah, yes, about that," she said, looking apprehensive. "Well, when we found you like this, I decided to clean up your room and get rid of your clothes and some other things you won't be needing anymore. I looked, but I couldn't find it, so I'm afraid it must've been one of the things that didn't make the cut."
"You didn't..." Jon said, her voice barely more than a whisper. Jon's mother nodded, and Jon's head reeled. The garbage man had come while she was on the toilet; she'd heard the garbage truck's aging diesel engine pull up and then drive away. By the time they could catch up, the stone would be buried under compacted tons of waste at the county landfill. Unless there was some secret spellbook or magic potion out there to restore her to normal form, she was doomed to life as a mermaid.
"I can't even begin to apologize properly," Jon's mother said. "I had no idea it was from Grandpa. I know how close you and he were, and at a time like this, I'm sure it must be even more terrible to lose something like that. I can't tell you how sorry I am."
Jon didn't hear her. She was too busy crying.