For Kaia, setting foot outside can be deadly. Climate change has made Earth too dangerous for people to live anywhere but inside the City. Run on the energy created by its Citizens and sustainable in every way, the City uses microchips, called pulse points, to control the energy its inhabitants use. When Kaia's pulse point malfunctions, she experiences freedom from the strict City rules for the first time in her life. With unlimited energy, she doesn't need to run for hours on a sensor mat, and she can share energy to hide her grandmother's failing health. But a shocking discovery makes her question what goes on inside the City walls and sets her on a journey to discover the world outside them.