Nicholas and Alisoun make a plan that will enable them to spend the entire night together in bed without John's knowledge.
Nicholas goes into his room, taking with him enough food and drink for a whole day.
He tells Alisoun that if John asks about him, she should say she doesn't know where he is, that she hasn't seen him all day, she thinks he might be ill, and even when her maid called for him, she received no response.
Nicholas spends the whole Saturday in his room.
On Sunday, John begins to worry about Nicholas, wondering aloud if he has died.
John sends a servant to knock on Nicholas's door.
The servant knocks hard on Nicholas's door and asks him how he can sleep the whole day away.
Upon hearing nothing from Nicholas's room, John's servant peeks through a hole in the wall and sees Nicholas sitting bolt upright and gaping, as though he's looked too long at the new moon (meaning, he looks crazed).
The servant tells John about the condition in which he found Nicholas.
John declares that Nicholas must have meddled too much in astronomy and thus gone mad.
John says that men should not know too much about God's secrets: it's much better to be an unlearned man who only knows his Apostle's Creed.
He tells about another clerk who spent too much time doing astronomy. That clerk was star-gazing in a field in an attempt to tell the future, and he fell into a pit instead.
John says he is sorry for Nicholas, who will suffer because of all his studying.
John tells the servant to push on the door while he pries at it with a stick.
The servant manages to take the door off by its hinges.
Nicholas is sitting as still as a stone and gazing up at the ceiling.
John thinks Nicholas is in despair. He shakes him by the shoulders, pleading with him to wake up.
He makes the sign of the cross on Nicholas against elves and demons and says a prayer at the four corners of the house in an attempt to exorcise from Nicholas the spirit he thinks has captured him.
Nicholas appears to wake and sighs, wondering aloud if the whole world is about to be lost.
John asks him what he means.
Nicholas tells John to fetch him a drink, saying that he wants to speak privately to John about something that concerns them both.