"I will later" said Amy.
Leaving a towel by the pool for Lina, Amy went back inside to wait for Mark. As the minutes passed, Amy decieded she should change her clothes. She went to her room, removing her panties so they wouldn't be shredded when her legs transformed into a tail. She was in the process of switching out her blouse and bra for a bikini top when she heard the front door open and close. Surely it was her boyfriend.
"Mark, I'm in my room" she called out and hurried to finish changing.
---
Mark found Amy's front door unlocked and, since Amy was expecting him, entered the house without knocking. He was surprised to find nobody in the living room. He heard something that sounded like Amy's voice, but couldn't tell where it was coming from or what she said. Walking through the house in the general direction of the noise, he heard a splash from the pool. Figuring Amy must be there, he went out the back door. A head popped up at the edge pool, but he recognized it as Amy's friend Lina.
"Hi, Mark" said Lina, resting her arms on the edge of the pool.
"Oh, hey, Lina" said Mark. "Where's Amy?"
"I dunno. She left me all alone in the pool." After a moment she added, "You should join me for a swim."
"Well, I should find Amy and..."
Mark's words trailed off as Lina pushed off from the edge of the pool and rolled backwards, giving Mark a good view of her soaked white blouse clinging to her ample chest, followed by the sight of her lilac fish tail. Lina waved her tail at Mark before it slipped under the water. Making a full underwater backflip, Lina surfaced again.
"You're a mermaid!" exclaimed Mark.
"A lonely mermaid" said Lina.