A girl of 5 is playing cards with her brothers in a gazebo when suddenly she sees a spectral hippopotamus ''rising from the ha-ha.'' ''Fly at once!'' commands the hippo. ''The Admonitory Hippopotamus, or Angelica and Sneezeby'' is a vintage Gorey story. Presumably the hippo will be more admonitory than it was on Cape Cod.

The show, with some revisions and now titled ''The Gorey Details,'' is scheduled to open tonight at the Century Center for the Performing Arts in Manhattan. ''It was more admonitory than we imagined.'' Among the items they found were drawings Gorey had started for ''The Admonitory Hippopotamus,'' an unpublished story that was a featured part of the Provincetown show. On one trip to the Gorey house, he was accompanied by Kevin McDermott, a producer and actor who has been involved in several theatrical anthologies of Gorey's work, including one called ''Amphoragorey,'' a musical presented in 1999 in Provincetown, Mass. Brown said, a trove of Goreyiana, with ample material for many future books and for plays based on his work. Amid the cosmic disarray, he discovered hundreds of stories and sketches, some finished, some unfinished, left behind by this grand master of the macabre.

Brown began searching through closets, crannies - in Gorey's words, ''beneath the floor, behind the door'' - and possibly up the chimney. After Edward Gorey died in April, Andreas Brown, one of the executors of his estate, visited Gorey's 200-year-old 15-room house in Yarmouth Port, Mass.

The Object-Lesson by Edward Gorey