The Cylinder is a massive structure rising miles above the surface of an unknown future Earth. Axxter, the hero of Farewell Horizontal, has forsaken the dull, nine-to-five life of Cylinder's Horizontal levels to go where the action is - the Vertical, where freelancers, warring tribes and other nomadic types live along the slings and cables of Cylinder's outer edge. His dream is to be a successful graffex artist, designing armour and ikons for the various tribes - and, like all citizens, he is linked by a microchip in his brain to the complex computer system that runs the economy. But when Axxter accepts a really big job - creating all-new military imagery for one of Cylinder's most powerful tribes - he begins a dangerous journey that will take him to the far side of Cylinder - and beyond.