Beyond the Grid - The Runners Series - Book 1

In a world ruled by the Elms family, Cassie and her sister Gusta are lower Grade workers in Driven City. In all the cities, everything from where which workers work, live, to what which workers are allowed to eat depends on the workers' Grades and the ruling family's laws. When Gusta and her secret lover Coleson leave Driven City, Cassie and her friend Axton leave everything behind and venture out into the unknown outside to search for them.
How will they survive all the unknown and hidden dangers on the outside? Why does Cassie keep seeing fire?