1887. The streets of Edinburgh seethe with youthful anarchy as two rival gangs of students, Scarlet Runners and White Devils, try to outdo each other in wild exploits. After a pitched battle between them, an old woman is found savagely battered to death in Leith Harbour. Enter Inspector James McLevy, a little more grizzled, but unchanging in his fierce desire to mete out justice. As the inspector delves further he meets up with one Robert Louis Stevenson, author of Jekyll and Hyde, in the city to bury his recently deceased father.