Mayhew is a professional actor, and the grown son of Mr. Pluto (Mr. Skinner). He's adventurous, mysterious, and fun. As you probably noticed, however, Mayhew is not all fun and games. He's lived out of town for years, and he's back on serious business, which is part of why he's angry. Happily, by the end of the story, he's taken care of business, and feels much less angry. Why, you ask? Because he's closer to his father and because he's stopped the Darrows from tormenting everybody on Dies Drear's land. What's more, Mayhew has made some very special new friends, the Smalls.
Mayhew and his mother left town when Mayhew was still a boy. Mayhew says, "My mother could no longer stand seeing the house or the townsfolk who thought we were strange" (14.24). Mayhew is mad because Mr. Pluto didn't come with them. He says, "We left it finally […] but my father wouldn't leave. I blame him for that. I still blame him for forcing us to leave" (14.27).
That sounds like a contradiction. Did the townspeople make them leave, or did Mr. Pluto? It's complicated, which is why Mayhew sounds like he's saying two different things at once. We think Mayhew means that he and his mother left both because the townspeople were mean and because Mr. Pluto's obsession over Dies Drear's treasure turned him into a person who was hard to live with. So Mayhew is mad at his dad for not coming with them when they left, and for not doing more to make it so they could stay.
This might explain why Mayhew isn't sure he likes his dad as a person. He tells Thomas,
"It's hard for a boy growing up without his father, not even being able to wish for him since he didn't like him to begin with." (19.57)
You can see that even though Mayhew is an adult, his childhood relationship with his dad is very much alive. Now, on top of all that, Mayhew is mad because Mr. Pluto has had the treasure for a long time, it seems, and he never sold any of it. Mayhew implies that he had to struggle hard for money, and especially as a boy, experienced poverty. He resents that his father could have used the treasure to help him financially.
Mayhew is also still mad at the townspeople:
"Calling my father the devil, as if being lame was a crime. Folks around here have been cruel to him for years – not only the Darrows." (15.7)
Still, he is really mad at the Darrows for tormenting his dad. His real reason for being in town is to stop the Darrows, and to get his father to the doctor. He's afraid his father is really sick, and he's a little mad that his dad won't get medical attention.
So, Mayhew is mad about a lot of things, but don't get the idea he's totally consumed with anger. He's able to work through it in some healthy, non-violent ways. It's also interesting to see how his anger at his father doesn't get in the way of his duty to him, a duty that's born of love.
When Mayhew and Thomas are walking back to the Smalls' house after they scare the Darrows, Thomas says something important to Mayhew: "You love it here. How come you go away from it?" (19.67). Mayhew's answer is very mysterious. He says, "That's my secret, my friend. […] Not all questions have answers to be said out loud" (19.68).
Hmmm. What does he mean by that? On the one hand, we can see it isn't practical for Mayhew to live there. In a bigger city (we don't know which one) he probably has more opportunities to earn a living as an actor.
Perhaps even more important, Mayhew feels trapped by the past when he's on Dies Drear's land. He says, "I take freedom any day over that romantic nonsense about slavery" (15.29).
Mayhew is suggesting that people like Mr. Small and Mr. Pluto spend too much time thinking about slavery and the past, and not enough time just living. The Drear house is a vivid reminder of a past Mayhew is trying to outrun. He doesn't want to be thought of as the great-great-great grandson of a slave, but as a man who has made his own way in the world, a world very different from the one his ancestors occupied. For him, freedom is an existence outside of history.
Considering what we know of Mayhew's bad experiences in town as a boy, he probably suffered a lot, and doesn't want to be reminded of the pain. Maybe the pain is too deep and confusing to be put to words. He's encouraging Thomas to put it together from all he's heard around him. An important thing to remember is that Mayhew still has a lot to work through. Meeting the Smalls, reuniting with his father, and stopping the Darrows are big steps on his path to a happier life.
By the end of the story, Mayhew has lots of things to feel good about. As we discuss in "Symbols, Imagery, Allegory" acting out different roles has helped him understand his father and feel that it's OK to love him again:
"But what I meant to say about being glad [about scaring the Darrows] is that my father had such a good time with it. I felt closer to him tonight than I think I ever have." (19.55)
Plus, Mayhew knows that the Smalls will look after his dad, so it's OK to leave him again. Mayhew would probably do anything to make sure his dad is safe, including moving back to the town. But, he has his own life elsewhere, and it would really hurt him to live here.
To make things even better, Mayhew and Thomas have become friends, and Mayhew wants to give something back to Thomas for his help with the Darrows – he wants to give Thomas the gift of acting.