College Student Rhonda Pineda (Shay Mitchell) joins a physics class at Ivy University in Connecticut, taught by Ray Palmer (John C. Mcginley). A “washed out” super scientist who uses unorthodox methods to teach his students. As well as being known for conducting unknown experiments after class hours.
After making the acquaintance of Ray’s T.A., Ryan Choi (Orsic Chau) looking to volunteer for college hours, she accidentally walks in on an experiment Prof. Palmer is working on involving, Dwarf star matter.
After being exposed to the experiment, Rhonda becomes unconscious and is given a special belt by Prof. Palmer to regulate the energy now surging through her body.
He explains to her about his experiments with White Dwarf Star matter and how he and Ryan had found that it had a strange effect on objects. Causing them to lose mass, but retain other properties.
Palmer also explains that the belt was made to siphon off any energy that might be exposed on him or Ryan during the experiments, but that he doesn’t know how it will effect Rhonda seeing as no one has ever been directly exposed before.
Rhonda eventually finds that she has the ability to shrink while wearing the belt. With Ryan’s help, she also finds that she can control her density at any size allowing her to either gain great strength or even be light enough to glide on air currents.
Using some various materials, Ryan makes her a suit and convinces her that she should use her powers for a purpose, to do some good in the world. Wary at first, thanks to the sudden change in her life, Rhonda accepts the idea and calls herself the Atom.
The two become a team, Ryan being her support and Rhonda doing the field work, looking for any problems they might be able to solve. Prof. Palmer acts as a mentor of sorts, keeping their secret as long as the two of them stay safe. Although he apparently has a few secrets of his own.