From the New York Times-bestselling Goosebumps series, a tween girl witnesses the librarian turning into a monster and everyone thinks she's lying.

She's telling the truth . . . but no one believes her. Lucy likes to tell monster stories. She's told so many that her friends and family are sick of it. Then one day Lucy discovers a real live monster: the librarian in charge of the summer reading program. Too bad Lucy's told so many monster tall tales. Too bad no one believes a word she says. Too bad the monster knows who she is . . . and is coming after her next.