Zippo aged 15 Mark Cummings and his younger sister Nelly Alex Stead live a tough lifestyle Their home is broken school is optional and their father Les Tony Howard is too wasted to notice what they get up to But a ray of light in their otherwise dark existence suddenly appears when they find a beaten up dog that has been dumped by a roadside The dog whom they name Carlos is quickly adopted by both Zippo and Nelly as they nurse him back to full fitness Despite him showing menacing tendencies whenever someone threatens the kids are unaware that Carlos has come from the brutal world of dog fighting Zippo in particular finds himself at odds with authority figures including the local cops who know him all too well