The Tunnel of Hugsy Goode

Nobody believed Hugsy Goode when he prophesied that a tunnel lay beneath the alley until-generations later-Nicholas (alias Copin) and Timothy (alias Tornid) decide to explore. And lo and behold, right under the vine-covered hole outside the house where Hugsy Goode used to live, they find an entrance to adventures beyond their wildest dreams.

A sequel to The Alley.