The city of Pendulum is a bustling city hiding deadly secrets - and Venice Rinalov and Tallion Starkven are caught up right in the thick of it. After hundreds of innocent citizens from the city of Pendulum mysteriously go missing, havoc and riots break through the clockwork city. Weeks later, the people return, and soon after, airships crash through the sky, steam trains skid off the tracks in a sickening metal clatter, leaving Pendulum on its knees like a wounded solder. Rumors weave through the city of Pendulum, whispers in the night that these incidents are not merely random coincidence, and, in the dead of the night, an alliance forms, by mysterious citizens of Pendulum known only as The Fireflies. 

Tallion Starkven, a former technojacker from the city of Noxwatch, and Venice Rinalov, a highly trained mechanic and a graduate of the Yarringtion Institute of Mechanics and Engineers; and from the city of Ivorymire join The Fireflies. They crusade through the city, determined to weave together the mystery of the two tragic incidents that struck Pendulum, and save the people and the city before the clock runs out.