Will their friendship ever be the same? Horace, Morris, and Dolores have been best friends forever. They do everything together—from sailing the seven sewers to climbing Mount Ever-Rust. But one day Horace and Morris join the Mega-Mice (no girls allowed), and Dolores joins the Cheese Puffs (no boys allowed). Is this the end? Or will Horace and Morris but mostly Dolores find a way to save the day—and their friendship?

Best friends Horace, Morris, and Dolores do everything together. So when they try out for the chorus and Dolores (who sings notes no one has ever heard before) doesn't get in, she feels hurt and angry and—not like Dolores at all—sorry for herself. But mostly she feels lonely, with her friends too busy rehearsing to have time to share adventures with her. So Dolores does what she does best and takes matters into her own hands. But can she prove to Moustro Provolone that there's a place for every kind of voice in the chorus?

Horace and Morris (but mostly Dolores) love cheese. To them, Swiss is bliss, Muenster is magnificent, and nothing’s better than cheddar. But everything changes when Dolores develops an allergy to her favorite food. Even worse, a food festival is coming to town, featuring—what else?— cheese! Fortunately, Dolores is one resourceful little mouse. And she comes up with a solution to her problem that is far from cheesy! Once again, the creators of the popular Horace, Morris, and Dolores books tackle a common childhood dilemma with verve and panache.