"After a tragic death at Fairview Public Library, frequent patron Mallory and community service volunteer Spencer discover they are not as alone, or as safe, as they thought." --,(Source of summary not specified)

Spencer volunteers at the library. Well, it's community service, but he likes his work. Mallory is sixteen and homeless. She spends a lot of time keeping her head down, trying to stay anonymous. When mysterious symbols and terrifying warnings begin to appear at the library, management grows suspicious. Spencer and Mallory know a homeless teenager makes an easy target. If they can't find the real culprit soon, they could lose more than just their safe haven. -- adapted from back cover