Bestselling writer Audrey Wood and artist son Bruce present a second alphabet book with a twist: a fun mystery that will let young readers learn their lower case letters without having to study! Engaging alphabet books are perennial bestsellers with unlimited demand. As in their previous collaboration, the Woods bring lower-case letters to life in a fun adventure. Little x has left, upset he's hardly used, and the other letters set out to find him. They find x playing the castle xylophone for the mysterious Master, capital M, who threatens to turn them into alphabet soup! Some quick thinking by Little x saves the day, and soon they are all on their way home — just in time to make Mom's birthday surprise: a cake with Little x all over. He's the only one who stands for kisses!