Sixteen-year-old Kali D'Angelo has always known she's different. Sure, she goes to high school and even attends pep rallies. But every other day, Kali becomes something else, hunting and killing demons, hellhounds and other supernatural creatures. On those days, she is indestructible. When a supernatural creat leaves the mark of death on a popular cheerleader, Kali knows she is the only one who can save her. There is only one problem. Today, Kali is only human.