I was in my room playing Pokemon when Mia came in and said, "can I borrow a pen? There are none in the junk drawer."

I pointed at my little desk where two pens were sitting.

"Thanks," she said, taking one. "Are these waterproof?"

"Do they have to be?" I said.

"Yes."

"Then they are," I said, figuring Mia would do the rest.

Mia's too little to disbelieve me yet, so she said, "okay."

"What are you writing?"

"A letter. Can I use your paper?"

"Sure. Letter to who?"

"My pen pal."

And she left before I could ask anything else.

The next day, I saw Mia slip something into the mailbox. "Who's your pen pal?" I said. We didn't know anyone who lived far away. "Is it a school thing?"

"No," she said. "Her name's marina and she lives at the ocean." She went to do homework and I peeked inside the mailbox. On the envelope were the words:

MARINA
ATLANTIS
THE OCEAN

With ten drawn-on stamps.

"They're not gonna take it," I said. But Mia didn't hear me.

The day after, Mia sent another letter. And another. She used up all my paper and started using the stuff for mom's printer. It wasn't until the end of the week that she finally got a letter back.

It was stuffed inside blue material sort of like plastic, and it was written on paper that looked like scales. It had seashells and shiny rocks stuck on it, and it smelled like kelp and salt.

"Can I read what it says?" I asked.

Mia hugged the letter to her chest and said, "No! She's my friend, not yours."

And ran upstairs, locking me out of her room.

Sisters.

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