I read this and the other S.E. Hinton staple books ("The Outsiders," "That Was Then, This is Now," and "Rumble Fish") repeatably as a teenager. This is one of the few Hinton books that will not seem as dated as others, as it is set in more of a country setting rather than city.
Of all of Hinton's protagonists, Tex is by far the most innocent and sweet, even referred to as Bambi by another character. More remarkably, Tex comes out of this book retaining that sweetness while coming to terms with a less than innocent discovery. Simply put, he a good boy repeatedly in the wrong time at the wrong place. He loves his horse and resents it bitterly when his older brother is forced to sell it in order for them to survive. They have an absentee father riding the rodeo circuit, and Tex's older brother has been forced to give up a basketball scholarship to attend to Tex's upbringing. As the book continues, his brother becomes increasingly frustrated and even violent, moreso than circumstances would call for. It is only when their father returns home, resulting in an argument between father and older brother, that a haunting secret comes out, causing Tex to run away.
Per his character, he runs to the wrong place at the wrong time, the city and an old friend of his brother who has built a life dealing drugs. The already upset Tex unwittingly arrives at a drug-deal gone bad, getting shot in the process. The shooting ironically causes a healing for his family, and an acceptance of the truth. The whole family learns to look past it and move on, growing.
Sharp-eyed readers will be able to find out what happened to Mark from "That Was Then, This is Now," as well as his particular relationship to Tex, unbeknownst to all.
I intend to give this to my son soon, for its lessons of blood being thicker than water, the dangers of drugs, and the inevitableness of growing up.