'Kneel' She Whispered by Kathi M. Nidd

Lucy, a young woman eager for a break from her job and her boyfriend, rents a beautiful lakeside cottage for a week of relaxation and alone time with her dog, Molly. But little does she know that secrets are lurking in the lake. After only a few hours, something, or someone, pulls at her leg from deep beneath the water. Rattled, but determined to enjoy her vacation, she retreats to the cottage where a whispering voice in the night leaves her shaking in fear as it guides her to "kneel" over and over again.