When her friend Monday Charles goes missing and Monday's mother refuses to give her a straight answer, Claudia digs into her disappearance.

"This is the story of how my best friend disappeared. How nobody noticed she was gone except me. And how nobody cared until they found her ... one year later." Monday Charles is missing, and Claudia seems to be the one person who notices. Claudia and Monday have always been inseparable - more sisters than friends. So when Monday doesn't turn up for the first day of school, Claudia starts to worry. When she doesn't show for the second day, or the second week, Claudia knows that something is wrong. Monday wouldn't just leave her to endure tests and bullies alone. With her grades on the line, Claudia needs her best - and only - friend now more than ever. But Monday's mother refuses to give Claudia a straight answer, and Monday's sister April is even less help. As Claudia digs deeper into her friend's disappearance, she discovers that no one seems to remember the last time they saw Monday. How can a teenage girl just vanish without anyone noticing that she's gone? In her dark, thrilling, and timely sophomore novel, acclaimed author Tiffany D. Jackson unravels a complex mystery and explores the traumatic effects of the truth. -- From dust jacket.