After lunch they all watched the carriages depart, and Brother Timothy, all smiles, reported that it had gone well. "The Bishop has agreed to let Brother Matthew be examined by the tribunal, provided the verdict sets no precedents," he told anyone who would listen. "So the police representative will be presenting the documentary evidence starting on Tuesday next week. Oberstleutnant Reishach wants this matter cleared up as quickly as possible, and says he must have a verdict by the end of the week, otherwise he will have to report the incident to his Colonel.

When he found them, Abbot Napp had the same tale to tell Brother Gregory and Brother Joseph. "It looks bad," he said, sadly. "But tell me, what have you found? And what was all that business of mud in the fireplace?

Before he answered the Abbot's question, Brother Gregory asked one of his own. "What did the porter say in his statement to the police?"

"Why, nothing," Napp replied, "as far as I know, the porter has not made a statement at all. Why should he, he was not involved?"

At which point the two monks told their Abbot about their findings, the mysterious lurker, the half eaten lunch, and the way in which the porter had been awoken and told of the fire. "It looks to us," Mendel concluded, "as if someone, possibly the saboteur, was watching the monastery and then broke in when he saw it was safe."

Abbot Napp, no fool, saw several problems with this theory right away, and the three of them talked about it for a while. "If nothing else," Napp said, "I'll be able to use this evidence to embarrass the police and cast doubt on the theory that no one but Brother Matthew could have started the fire. I don't think it will work, but it is always worth a try." He looked at Mendel. "But you still haven't told me about the mud."

So once again the scientist tried to tell the Abbot about the microscopic examination of the mud specimens and what they had found. He had to answer many questions, and repeat several parts of the story over again until the Abbot understood what they had done and what it all meant. "You mean," Napp said at last, "the mud left by the saboteur in the guest room was mud he could only have got on his boot by walking along Uzov road and passing the Beifuss bushes?"

"That's the most reasonable explanation of all the facts," Brother Gregory agreed.

"Well, well, well," grinned Napp, collapsing into one of Brother Gregory's better chairs. "This changes everything!" His grin became a laugh and as he laughed tears began to roll down his cheeks and onto his collar. "Brother Gregory, you are amazing! Do you realize what you have done?"

Completely surprised and shocked by the behavior of their leader, the two monks did not answer at first, and then only when Abbot Napp slowed down his laughter. "I'm not sure what you mean," Brother Gregory said. "That pollen is very common, and a lot of people walk along Uzov road at this time of year. I would say everyone in the monastery and certainly every one of the soldiers has some of it one their feet."

"Not quite everyone," laughed Abbot Napp, trying to control himself. "There is one very important person who I would absolutely guarantee has no Beifuss pollen on his feet, or anywhere else. Do you know who I mean?"

The two friends could guess, who else but Brother Matthew, but why?

"It is very simple," the Abbot told them at last. "Brother Matthew has hay fever, and he swears that it is brought on every time he goes near those Beifuss bushes. There is no way he could ever go close enough to get mud on his boots and not have streaming eyes and a red nose for days after! If you are right, and the saboteur in the guest room had pollen from the Beifuss bushes on his feet, it could indeed be anyone, but NOT Brother Matthew. You have just proved a negative!"