section: Overview
question: The series is split into how many different arcs?
article: Pretty Little Liars
candidates: The series is loosely divided into three arcs of four to five books each, chronicling the introduction and reveal of each "A". The series follows the lives of four teenage girls — whose names are mentioned above (nicknamed "the Pretty Little Liars" or simply "the Liars") — whose clique falls apart after the disappearance of their best friend, Alison DiLaurentis. Three years after her disappearance, they begin receiving text messages from an anonymous source, "A," who threatens to expose their secrets; including long-hidden ones they thought only their close friend Alison knew. But shortly after the messages begin, Alison's body is discovered. The books progress with the four girls trying to figure out the identity of "A".