something secret when he realizes that Winnie is watching him? Why won't he let her drink the water? These are the main questions that go unanswered in the reader's mind in Chapter 5.

Some readers might also want to know why Jesse seems to tease Winnie on the topic of his own age, and why he's reluctant to tell her how old he is. What is he hiding about his age? Why won't he just say right away how old he is? Why does he seem so serious when he jokes that he's 104 years old?

And when Mae Tuck arrives at the end of the chapter and sees Winnie near the stream, why does Mae say that the "worst is happening at last"? 

After we read beyond Chapter 5, we figure out what those missing details were:

1. Jesse had tried to keep the water source hidden because it's actually magic water that makes people who drink from it live forever. He didn't want Winnie to drink it; he'd rather everyone lived in a natural life span instead.

2. Jesse told the truth about his age being 104. He really has lived that long, even though he only appears to be a teenager.

3. Mae sees Winnie near the magic water, and she thinks Winnie knows her family's secret. That's why Mae thinks that the worst has happened.

I suppose a reader could list out a large number of details that are missing from chapter five.  A lot would depend on how obscure of a detail that a person is looking for.  For example, chapter five tells readers that "Winnie woke early next morning."  The text then goes on to say that the sun was just rising.  That's a good enough description for me, but precisely what time it is has been left out.  

Another simple detail that has been left out is Jesse Tuck's eye color.  The description of him is very detailed.  The paragraph about his looks is the second longest paragraph in the chapter.  Readers learn about his build, his curly hair and its color, the state of his clothes, and even the fact that he is holding a twig between his toes.  Jesse's eye color is not mentioned, which strikes me as odd, because eye color is a fairly standard detail that authors typically give about characters.  

One final missing detail from this chapter that I found unnerving during my first reading of this book is the fact that Jesse knows who Winnie's family is.  

"It's my wood," said Winnie, surprised by the question. "I can come here whenever I want to. At least, I was never here before, but I could have come, any time."

"Oh," said the boy, relaxing a little. "You're one of the Fosters, then."

The fact that Jesse knows about her family, and she doesn't know about him, doesn't bother her at all.  That's odd, if you ask me.  I would be immediately wary of somebody that I've never met that knows about me, my family, and what we do and do not own.  The detail missing from this chapter is any kind of information about why Jesse Tuck would know this information.