The road that led to our house continued a few hundred feet past it, into the state forest, marked by a sign that lectured on littering and swimming at your own risk. I went around the chain slung across the path, Poe a few paces behind me.

“Where are we even going?” Poe asked.

“It’s a place where your mom and I used to play,” I said.

“Yay,” she muttered.

We walked through the woods on a path springy with pine needles. The wind was gentle today, and the sky was achingly blue. Seagulls squawked overhead, and a crow fluttered from tree to tree, clicking occasionally, as if it wanted to be part of the conversation.

Poe almost walked into a tree, so busy looking at her phone. “There’s no cell service out here,” she said.

“Oh, well.”

“Stupid,” she muttered, shoving her phone back into her pocket.

“How have things been at school?” I asked.

“Fine.”

“Do you and Audrey ever hang out?”

“Not really.”

“Any other friends?”

“Is there a reason to make friends, when I’m going back to Seattle in a couple months?” she asked with exaggerated patience.

“You have a point,” I said. “But it might be nice to have a friend back here. For when you come to visit Gran.” I pushed a tree branch away from my face and held it for Poe. The smell of sea was stronger now. “By the way, I’d love if you came to visit me, too. Anytime. Maybe you’ll want to go to college out here. Boston has a lot of great schools, and so many great restaurants and things to do.” I sounded like a tourism brochure.

“Do you have an apartment?” she asked.

“Not at the moment. My boyfriend and I were living together. But before that, I had a really great place.” Best not to think about that. “Okay, we’re almost there.”

We came out of the woods onto the great golden slabs of rock that made up the shore. The tide was low, and the rocks were dark brown where the water had been just an hour before.

My feet hadn’t forgotten a thing. The cracks where I had to jump, the slanted rock that was perfect for pushing off, the little plateau with the best tide pool. Sure enough, two fiddler crabs were inside, skittering around each other in their own little world. I knew the way as if I’d never left the island.

There was the rock that looked like an old lady in profile, then the rock Lily called the Tooth, because it had little ridges and bumps, like a molar.

And here we were. I jumped down onto the rocky little beach. “Ta-da,” I said, waving my arm like Vanna White, pretending it didn’t hurt my heart, seeing this place again. “Come on in.”

To access the entrance to the cave, you had to go out a bit. Unless the tide was dead low, as it was now, your feet would get wet. At high tide, the cave was underwater. I led the way, my shoes crunching on the pebbles that made up the shallow beach.

Inside, it was damp and briny, and memories flooded in like a storm surge.

I could almost see Lily, her unexpected, booming laugh as she crouched next to me. Her sweet smile, the dimple in her left cheek, her shiny black hair.

Poe followed me inside. Even she couldn’t look disinterested in this. “Cool,” she said, her mouth opening a little.

“We used to pretend this was our house,” I said, more to myself than Poe. “We’d drape seaweed over the opening to make a door, so none of the fishermen could see us from the ocean.” I pointed to a spot in the back, where the cave narrowed and a piece of rock jutted from the shore, making a surface that was more or less flat. “That was our bed.” I’d hold my sister against me, since it wasn’t quite wide enough for two, her skinny little body snug against my side.

I swallowed. “We’d set up rocks here and pretend to have a fire. Sometimes Gran would make us peanut-butter-and-apple sandwiches, and we’d eat them here. The seagulls would follow us in to get a bite.”

And then later, when Dad was in charge of us, we’d do what he called the Cave Challenge—who could stay in the longest as the cave filled up with water? It was a survivalist skill, he said, and I remembered the terror as the water came up to our knees, our waists, our shoulders.

I was always the first one out, waiting anxiously on the Tooth for their heads to pop up in the water. Dad and Lily would stay in there till I was terrified they’d drowned, and just as I was about to go get help, there they’d be, laughing, gasping, triumphant.

I wouldn’t tell Poe about that.

The cave was big enough for us to stand, but not much else. Like so many things from childhood, it seemed to have shrunk. But it smelled the same—the wet, cold rocks, the salt water that slushed and slapped.

“Your mom and I thought we were the only ones who knew about this place,” I said. “Our Dad, too. But we made a pact never to show anyone else.”

“Did you ever?” Poe asked. “Bring someone here, I mean?”

“Not until today.”

“Did she?”

Maybe she had. Maybe she’d come here with the boys she’d slept with, or with Amy Beckman to smoke weed. The thought stabbed like a dull spear. If Lily had made fun of me here, if she’d mocked our little games, if this place wasn’t as sacred to her as it was to me...

“I don’t know,” I said, my voice husky.

It didn’t matter. She’d given me up a long time ago.

A little wave sloshed over my shoe. “We better go,” I said. “The tide has turned, and it fills up fast. It wouldn’t be hard to drown in here.”

“Yikes,” Poe said. “Nora...”

Funny, I couldn’t remember her saying my name before.

“Yes, honey?”

“Thanks for showing me.”

“You bet.” I smiled at her, and she almost smiled back.

When we got back to the house, my mother was home. I glanced at my watch; lunchtime. Mom often came back home to eat or, more often, brown-bagged it. Never bought something from town, never went out. That would be wasteful.

“Hello, you two,” she said.

“I’m going to my room,” Poe said. She gave me a look, then, shockingly, a shy hug, fleeting and all the sweeter because of it. My throat tightened.

“Are you coming over for dinner?” I asked.

“With all the old people? Uh, no. Thanks.” She rolled her eyes, but it wasn’t with the usual disgust, then went upstairs.

Mom was in the kitchen, glancing through the mail. I sat down at the table. Like everything in the house, it was sturdy and worn, just like my mother. Last weekend had been Mother’s Day. I’d given her a gift certificate to a spa in Portland—manicure, pedicure, facial, same as I did every year. But this year, I saw her tuck it in the spice rack, and when she was out of the room, I went to check. Sure enough, there were all the other gift certificates from all the other years. She never used them.

Then again, she always said what a nice gift it was. She was an enigma, my mother.

“How was your day, Mom?”

“Fine. Yours?”

“Lovely. I can’t wait for our little dinner party later on.”

“About that, Nora. I really don’t want to come.”

“But you will, and you might even have fun.”

She snorted, then opened the fridge to make herself a sandwich. Same sandwich she always ate—two slices of chicken, one slice of American cheese, mustard and butter, whole wheat bread. She saw me watching. “You want one?”