How She Forgot Her Ex

Lena's life was shattered after she was cheated on. Her friend Mindy set her up on several lame dates, one after the other, until she met Tom, a man who had the secret that she needed. "Set this black stone in water and you will never think about your ex ever again." It seemed too good to be true--a black stone? "What on earth it would grow into to make me forget my ex?" but it came with a catch. "There is a red stone you must feed it to kill it after one week.
You won't want to... but you must, and if you don't, then no woman in the whole world will be safe." Lena was willing to do anything to forget about her ex, even betray humanity itself.