What happens in Chapter 17 of The Egypt Game?

In Chapter 17, entitled "The Oracle Speaks", the Egyptians meet in the alley and enter Egypt all together so no one will have a chance "to fool around with the Oracle before everyone (is) there".  April takes charge, handing out costumes to everyone, then she begins the proceedings.  Ken, who yesterday left a question for the Oracle by writing it on a piece of paper and slipping it into Thoth the Owl's beak, is a famous general, and the rest of the children are priests and attendants of the Oracle.  As the high priestess, April leads a procession around the yard, then approaches the altar alone. 

April bows low before the Oracle, and, after performing an elaborate ceremony, begins a chant in which the others join in.  Suddenly she cries, "Stop!", and proclaims that "the mighty Thoth has heard (them)".  Taking the message from the beak of the owl, she reads it carefully, then turns it over and is shocked at what she finds on the other side.  Angrily, she stomps out of the temple, and when the others follow, she confronts them, asking which of them touched the message after it was placed in Thoth's beak yesterday.  April shows the Egyptians the message.  On one side is the question Ken had written, but on the back is a cryptic response in an unfamiliar handwriting.  Everyone proclaims their innocence, and an argument ensues.  Melanie finally makes peace by suggesting that they try the whole thing again, only this time they will all watch each other carefully to make sure no one goes back to write an answer.

April decides on a question and writes it on a clean sheet of paper, showing the others that the back of it is clear before she folds it and presents it to Toby, who will place it in Thoth's beak.  Even though everyone is certain that one of them is the culprit, there is an atmosphere of spookiness as they go through their ritual.  Suddenly the Egyptians are startled by a "huge shuddering thumping noise".  They run outside and discover that it is thunder, and that it is beginning to rain.  Quickly, they scramble for the hole in the fence, anxious to get out of Egypt (Chapter 17).