Alexandra "Alex" Mack is an ordinary teenage girl living with her parents, George and Barbara, and precocious older sister, Annie, in the industrial town of Paradise Valley, Arizona. The town is largely funded around Paradise Valley Chemical, a chemical factory that employs most of the adult residents, although the factory's staff and history are notoriously shady. While walking home after her first day of junior high school, Alex is nearly hit by a truck from Paradise Valley Chemical, and during the incident, she is accidentally drenched with GC-161, an experimental substance developed by the factory. She soon discovers that it has given her strange powers, including telekinesis, shooting electricity from her fingers, and the ability to dissolve into a mobile puddle of water. Alex finds this exciting and fun; however, her powers prove to be unpredictable (occasionally, her skin glows a bright yellow when she is nervous). She confides only in Annie and her best friend Ray, choosing to keep her powers a secret from everyone else, including her parents, for fear of what the chemical factory's CEO, Danielle Atron, will do to her if she finds out.
