Ard'rian McKenzie was a Human colonist on the planet of Tau Cygna V in the year 2366. A descendant of the original settlers who arrived on the SS Artemis, she had a keen interest in cybernetics. Like all the other colonists, she was immune to the effects of hyperonic radiation.
When the Sheliak demanded that the colonists be removed from the planet, which they owned, she helped Lieutenant Commander Data of the USS Enterprise-D, who was assigned to arrange the evacuation. Initially, she was the only one who believed that there was a need for evacuation, strengthened by her belief that androids were more trustworthy than Humans.
She became fond of Data, and was disappointed when he revealed that he had no feelings for her, as he had no feelings of any kind. Eventually, Data managed to convince the other colonists of the need for evacuation, thanks in a large part to McKenzie's help. Data actually kissed her as he was about to depart, noting simply that she seemed to need it. (TNG: "The Ensigns of Command")