The House is offended by your frivolity. Unspeakable horror from the nether beyond is serious business! In a fit of high dudgeon, it collapses the rest of the corridor, sending your "party" into the torrent of the waterfall and the depths below.
When you finally come to, you find yourself in a deep cellar. It is clear from the regalia of the room that this is the building's chapel; although the underground room has no stained glass windows, it still has swathes of moulding brocade and many valuable-looking ornaments, including a large gold and silver-plated cross. The waterfall has plunged through the wooden ceiling but the stone floor proved to be too much for it; fortunately for you, the water is draining out via a ruptured sewage pipe to the south.
There is only one door - to the north - and it is closed, and at this you discover a problem that needs your solving. It seems that most of you have shrunk in the wash. Following your plunge, nine of you are now less than six inches tall, and talk like you have been sucking helium. The tenth is Heisenberg Cat, who, being mostly made of fur, has expanded to over eight feet.
Most of you can't reach the handle, and the one who can can't fit though the door. (Also, doesn't have thumbs.)
To further complicate matters, a note that fell down with you details one player's suspicions and plans for an exorcism. The target appears to be Philbert Julian Cadweller (Kramer).
Despite being in the temple, you agree that too precipitous an action could have disastrous consequences, and resolve to put the accusation to a vote.