The vertical world. The age of steam machines has been replaced by the era of aponite engines. After becoming a victim of the Industrial Revolution and falling into poverty, a young scientist, Syairan, sets out to search for treasures that fell at the foot of his world—the rock of the Millennium Bastion. No one believes in the success of his expedition, except for his loyal maid, his friend the inventor, and the suspicious adventure hunter, Nelly. So what awaits the aristocrats who dare to descend into the mysterious abyss beneath the Bastion, which until now had been only a subject of rumors?