u/songwithoutamelody

I don't remember anything about the title or genre, or even exactly read it. I'm pretty sure I read it sometime in between 2010-2020, and I know I borrowed it from an English teacher, although I don't know what grade. All I really remember about the contents of the book is that some boy(or girl, not quite sure) had this dog and they did sled races, and I really liked the book until the end where the dog had a heart? Attack and died after winning/losing a sled race. I remember stopping reading after that point because i was a sensitive child who hated sad books, but nowadays I am really interested in reading it again. It's likely a children's book, but I am not 100% sure

Sorry if this is a bit nonsensically formatted, this is my first reddit post gulp