Complex sentence: Arthur talks to the Raised Rats, a group of anthropomorphic rats brought to the House by the Piper, and makes a deal with them to take him to Feverfew's hideout, which they believe is inside Drowned Wednesday, in a worldlet within her stomach.
Split into simpler sentences: Arthur talks to the Raised Rats, a group of anthropomorphic rats brought to the House by the Piper, and makes a deal with them to take him to Feverfew's hideout. They believe it is inside Drowned Wednesday, in a worldlet within her stomach.