The Witches of Isle Royale 3: Remember Me - The Witches of Isle Royale, #3

When nothing is like it was... In the deep forests of the prohibited Isle Royale in the far northern reaches of Lake Superior, Kim Murayama lives quietly with Mick, one of the mysterious Royale "witches" cloned by the Wilmut Corporation. He's at peace except for one thing - Wilmut's genetics have decreed that the Royales will die at 30 years of age. Mick must die. But what if it were possible to disconnect the OFF switch? There may be a way to save Mick and her sister witches from their preordained dissolution, but it won't be easy.
Wilmut, Inc. wants her back in the lab, and the Darkness - that malignant, discarnate evil from another dimension - wants them all dead.