[2] Tess Avery is former homicide detective who, in the middle of a case, suddenly starts losing her vision.

Within days she is forced to leave her job after being diagnosed as clinically blind, due to the fast-onset genetic condition Leber's hereditary optic neuropathy (LOHN).

She tries to remain as independent as possible, while trying to navigate the world with her severe scotoma-type low vision.

She said that the producers of the show had been aware of this, and "I think they were looking to specifically cast somebody that has real life experience with" vision issues.

[1] The show's focus on a visually impaired woman received some attention as a significant advance for media representation of people with disabilities, as it premiered around the same time as One More Time, a Canadian comedy series on CBC Television about a hearing-impaired retail manager.