How many times have you reached the end of a drama and wished it hadn't turned out quite the way it did? If only your hand had been on the steering wheel and you could have stopped the hero from drowning, or called the fire brigade in time to stop the grand mansion burning down. Some Dogs Bite (BBC3) is a drama that offers that option. You get the chance to go online and twist the outcome by allowing its central character, the taciturn H, to explore variations on his fate. It opens up a roundabout of possibilities, the turning you take deciding the fate of H and his two brothers, teenager Casey and baby Severino. I'm wary of interactive drama. Too often it's simply used as a cop-out by writers and directors who can't quite make up their minds, like a dance track where endless remixes obscure the quality of the original. But Some Dogs Bite sidesteps those concerns, driven by a genuine desire to open up the options to characters who, to put it mildly, have had a rough ride. H, Casey and Severino are orphans, half-brothers born to the same mother and three different fathers. Their mother is dead, the fathers are absent and they face life on the run when Casey snatches Severino from care. On these lost souls director Marc Munden and writer Lin Coghlan hang a haunting portrait of fractured lives on the fringes of society that neither romanticises nor judges its subject. Boasting impressive performances from Aaron Taylor as the struggling H and Thomas Sangster as the other-worldly Casey, Some Dogs Bite does bite. It makes you want to explore the machinations of social services as you get inescapably involved with the different lives the boys could have had, as opposed to the fate doled out by the drama on screen. Some Dogs Bite worked fine as a stand-alone film, a silent and occasionally shocking road movie about boys on a collision course with a dead end. But getting the chance to intervene in their fate, to not just turn a blind eye, meant this moving story's teeth marks lingered in the flesh long after the credits rolled.