"After returning to the bedroom, Wisdom fell to his knees with a thud as cold sweat dripped from his forehead."
How could this be?
"He ran to the bookshelf and took the Hikasa Manual that he had gotten from Longford County and looked through it bit by bit, afraid that he might have missed something. Unfortunately, after reading the entire book, he couldn't find anything that would help Nathaniel's."
Nathaniel was clearly poisoned!
Wisdom knew that Nathaniel wasn't poisoned out of the blue and that the poison was accumulated over the years.
But how was that possible?
"Daddy had always been in good health, so even if he was poisoned with something that would kill him slowly, someone would have noticed changes in his health eventually."
"For so many years, Nathaniel had Noah close by his side and Noah should have been able to find out about the poisoning. But why didn't he?"