I just saw this on the yareads.com site. It looks like Maggie Steifvater’s sequel to “Shiver” which is going to be called “Linger” has had the cover released along with a blurb about what the book will be about.
You can find all of this info here.
I have pasted the cover picture in below. I like it; it matches the cover for “Shiver” and is simple yet intriguing.