Scaredy-Pug: A Branches Book (Diary of a Pug #5)

Baron von Bubbles (Bub) the pug, Duchess the cat, and their human, Bella, are going to the countryside to visit Bella's grandmother for a few days, where they expect to have fun building forts and dressing up in the attic--but the attic seems to be haunted, and neither Bub nor Duchess can summon up the courage to face the ghost.