Ben Tomlin has to move with his parents all the way to the other side of the county (his country - Canada) because of his father's job. Ben's dad is a scientist who wants to be involved in the project of a lifetime. Dr. Tomlin wants to teach language to a chimp in order to prove that chimps can master language. Dr. Tomlin got a new university to sponsor his project. So Ben's life was turned upside down. Not only did he have to move, but he also got a new "brother" - Zan the chimpanzee.
At first Ben wasn't too fond of Zan, but as time goes by, Ben sees just how smart Zan is. Once he gets past the poopy chimp diapers....Ben begins to love all the time he gets to spend with Zan. Zan picks up the language (American Sign Language) quickly, and all seems to be going well. But Zan is a chimp. Is he really learning language or just imitating what he sees the humans do around him? Will he be able to initiate conversation or will he only answer when spoken to? What do you do when the baby chimp becomes a full grown male chimpanzee who is much stronger than any human? These are all questions that come up in Kenneth Oppel's Half Brother.
Also in the background of all this is Ben's life. Can you be a normal teenager if your dad is running this experiment. He's got camera crews in his house. People are talking about whether or not his dad should even be using an animal in this way. All this complicates what is already a hard time of life for a teenage boy.
I loved this book. I fell in love with Zan just as Ben and his mother did. I felt like he was just as strong a character as the others who can talk and are like me. This book is a great story about Zan learning language, but it's also about fitting in, dealing with family and relationship issues, and making tough decisions.