The Rebirth of Wonder

Art Dunham had worked in his father's small-town New England theater all his life, and had never before seen anything like the group that rented it one summer. They said they didn't need lights or props or sets or costumes, and they did nothing to advertise their show. The Bringers of Wonder, as they called themselves, wanted to put on a single performance of a play called "The Return of Magic" -- but is it a play, or something more? The troupe's leader calls it a classic, but Art can't find any mention of it in the local library.
As if that wasn't enough, as the rehearsals begin Art starts to find odd little things -- doors he never noticed before, things in the theater basement that shouldn't be there, and more. What are the Bringers really up to -- and should Art help them, or try to stop them?