Bobby O’Brien, a precocious and energetic 11-year-old boy is obsessed with becoming a great detective like his television hero Kojak. Set against the backdrop of 1980s working-class, inner-city Dublin, Bobby and his pal Nell torment their family, friends, and neighbours as they set up their own private investigation enterprise. When Bobby’s big brother Oisín disappears Bobby and Nell must embark on a quest to find him.