Wishbringer

It's an ordinary day in your ordinary little town, and you've been performing your ordinary mail clerk's duties in an altogether ordinary way. But there's something quite extraordinary in today's mail. It's a ranson note for a kidnapped cat, and it will lead you through unbelievably harrowing adventures to Wishbringer, a stone possessing undreamt-of powers. For though the note in question is addressed to someone in your ordinary little town, it's postmarked for Special Delivery to Parts Unknown. And its true destination is somewhere beyond your wildest dreams, c/o the magic of Infocom's interactive fiction.