For the majority of The Secret Hour, Jessica's ability is unknown. At the conclusion of the novel, it is revealed that Jessica is a "flame bringer", a rare talent that allows her to create fire and use electrical devices during the Blue Time. This makes her a valuable addition to the team, as she can use this ability to be a formidable opponent against the darklings, who fear light, fire and technology. Her first use of this power was a flashlight initially named Serendipitous. As both fire and technology can be used outside the blue time, Jessica's power is effectively useless in regular-time. (However, she is the only one who does not suffer adverse effects from being in daylight; Rex is effectively blind, Dess becomes photophobic, Melissa is plagued by the thoughts of humanity, and Jonathan must constantly shift between low and normal gravity)