Sissy and Lola are best friends, next-door neighbors, and now... murder solvers? When Sissy picks up a lost flip-phone and follows the instructions from the stranger on the other line, she and Lola are flung into an investigation of a grisly crime. With each new phone call, the girls are dug deeper into a conspiracy that threatens their lives—and possibly their friendship. But with no way to escape the dreaded calls, the only way out is to unravel the mystery.