the last sunset i ever saw

It was getting along toward summer, and the sun was sinking slow and lazy in the sky. The clouds hung low and jagged in the distance like a stretch of snow covered mountains over the lake. We walked down from the lake house together to sit at the dock. I trailed a couple feet behind her, half because I wanted to watch her walk and half because I was afraid I'd trip over a tree root or slip in a puddle of mud. She trekked fearlessly through the trees. She stabbed at the dark soil as she walked with a big branch she'd picked up. I told her to be careful because she might get splinters in her hands, but she ignored me. We came to the dock and she threw down her walking stick. She walked to the edge of the dock and stood with her arms outstretched and her face toward the sun. I picked up her stick and watched her turn orange under the setting sun. She turned her head and squinted over her shoulder at me. 
"Leave my stick alone." 
I dropped it and I was embarrassed. 
"Are you just gonna stand there all day?" She sat down on the edge of the dock and dangled her feet in the water. I walked cautiously to where she sat. She scooted over to make room for me, but I didn't sit. I stood in her shadow and watched her swing her feet. The lake reflected the sky and her kicking feet sent ripples through the cloud mountains. The hairs on her arms shone golden against her olive almost-summer skin. She had a little mole on her wrist. She stared out into the lake and furrowed her eyebrows at the sun. 
"Why won't you sit next to me?" She kept her eyes focused on the horizon. 
"I don't want to put my feet in the water.", I said. I was embarrassed again. 
She spun around and glared at me. "Why not?" 
I thought for a moment. "Because I'm afraid that something will come out of the water and pull me in. I'm scared of lake monsters."
She laughed and shook her head so that her pretty hair glittered in the sunlight, and I laughed too even though I didn't think anything was funny. The sun had dipped below the trees on the other side of the lake, and the water was turning darker by the minute. It was getting cold. Her pretty feet splashed around in the black water and all I could think of was something blue-purple and pale and dead and bloated floating up to the surface and grabbing hold of her skinny scabbed up ankles and pulling her down into the darkness. I looked down into the water and all I could see was her face, eyes wide and bubbles pouring out of her mouth open and gaping in a soundless scream, and her shiny-new-penny colored hair dancing around her face as it disappeared into the depths of the lake. I squeezed my eyes shut tight and tried to think of something else. The mole on her wrist, the little secret smile in her eyes that she didn't want anyone to see. I shoved my hands into my pockets and stared at the back of her head. 
The sun had altogether disappeared and the sky was turning from barely purple to dark blue. She stood up and surveyed the vast, quiet water. She turned around to look at me and she took off her shirt. I looked down real fast and stared at the ground and shuffled my feet on the rotting wood. I saw her shorts drop around her ankles and I saw her pretty feet step out of them and walk to the edge of the dock. She slipped soundlessly into the black water and swam out a few feet. She turned toward me with her nose and mouth underwater, and I saw only her eyes, big and mirror-like in the dying twilight. She swam out into the waking, breathing night. I turned around and walked back to the lake house alone. The night came alive and swallowed everything whole.