Losing and finding my sister had been all glossy shadows. My glasses were greased over, and my arms and legs were shorn with slivers from leaning against the boathouse door.

"How did this happen?" Dad asked me while trying to unlock it. He was breathless, panicked. He looked like the rabbits found in the yard at night. I turned the flashlight on them and their eyes scream back, wide with shock. I had gone for help after I realized the rusted latch had jammed.

The door opened with a slippery moan. From the darkness, Shelly crab-walked onto the grass and collapsed into my mother's outstretched arms. A spider leapt from her hair and skittered back into the boathouse. A bite on her elbow dribbled a spot of blood.

"Mary did it," she said.

It was unavoidable at this point.

Shelly told our parents I had asked her to grab the fishing tackle box so we could drop bobbers on Pistakee Point. I had closed the door.

It was supposed to be a prank. How many times had Shelly locked me in the bathroom, or jammed a chair under the closet doorknob while I picked out a dress? Shelly was a shadow; she was always so good at hiding.

My parents glared at me.

"Away," my mother whispered. She waved her hand as if I were something to swat.

They scrambled, moving my things from mine and Shelly's shared bedroom to the den. I tried to apologize, tried to tell them Shelly did it to me all the time. But some of the bites were swelling purple and green. They cradled Shelly to the car and drove to the hospital.

"We'll deal with you later," they said.

While they were gone, I went into our bedroom to grab the dreamcatcher on the corner post of my bed. The wax thread was dotted with glass beads, forming a web that, when the sun hit just right from our window, flowed my pillow with color. Shelly had made it for me years ago at summer camp.

"To save your dreams," she'd said. It was the last truly nice thing I remember her doing for me, amongst all the scares, the shadows, and games. She had never been afraid of dark corners, cobwebs, or the like. That's why I thought my prank was okay. She hadn't even screamed. In fact, I don't remember hearing a sound, only that she had been in the dark of the boathouse for long, long time.

"I still don't understand," my father whispered in the hallway. "What the doctor said—it doesn't make any sense."

Later in the night, I woke up. At first I was lost, forgetting I was in the den. I thought I heard hissing. Throwing off the blankets, I snuck from the couch and walked to our bedroom. Inside was Shelly, ridden with bandaged arms and legs. She had stripped both our beds to the mattress. She was crawling and rubbing on mine. The markers from her desk were strewn about the room. Her hands moved rapidly — she was drawing: Little daddy longlegs and brown recluses scurried over the bed. Wolf spiders and tarantulas. Spiders with legs as thick as branches. A mother spider cradling her eggs. A mother spider eating the father.

"Shelly?" I asked.

"It's your fault," Shelly said, her head snapping up. Her eyes seem to have multiplied in the darkness. Something sour and biting filled my belly. It felt similar to the times when I ate too much dessert, knowing that it hadn't been a good idea, wishing I could take it all back.

I watched my sister until my eyes went raw from dryness. I watched her draw, her movements frantic and rigid. Her teeth chittered like before. A steady click-click. Eventually, Shelly stretched out and fell asleep on my mattress, snuggled atop her weavers. I retreated, backing away slowly to the den. Once inside, I pushed the button on the doorknob to lock it. This was all a misunderstanding, I thought. Just an accident.

I remembered reading from one of Shelly's favorite books, that if all spiders worked together, they could eat all humans in a year. One year. I imagined my dreamcatcher riddled with more than glass beads. I imagined a world twirled in silk—a world locked tight. I tried not to sob as I gazed at every crack and corner in the room, each shadow filled with possibility.