Benny and his sister Penny know it's wrong to sneak into someone else's backyard but their mysterious new neighbor--or is it a monster?--may be a thief. They go snooping and discover a lot about themselves and...a new friend.Bestselling children's artist Geoffrey Hayes enchants early readers with his charming and subtle storytelling. In this lively caper, the artist's small-scale mice take on large-scale issues with enormous comics mastery.