Alexa Bond was a mortal woman working as a waitress at Joe's tavern in Seacouver.
Frequent patron, Adam Pierson/Methos, was strongly attracted to her, but put her off by being too cynical. Deeply interested in making a good impression, he tried again, and asked her out. She agreed to see him. Delighted, he told Joe he was her type after all, at which time Joe warned Adam that Alexa was dying.
She approached Adam later to break their date telling him she was terminally ill, but it made no difference to him and he insisted that they keep their date, "because the alternative would be unthinkable."
When she later stood him up, he sought her out at home and she warned him of what was to come for her; that she had a year or less to live. He dismissed her concerns as unimportant, because he would be there for her if she would have him and she can either spend the time she has left dying, or living...with him. He presented her with two airline tickets to anywhere, 'everywhere if there's time.'
The two started on Alexa's world tour "Adam likes to call it our tour of the new world," a cross country trip, to be followed by trips to among other places, Egypt, Israel, Italy, and Greece. She particularly loved Santorini, but three weeks after their visit there, her illness took a turn for the worst, and she entered hospital in Geneva.
Methos only left her side briefly on two occasions during their time together, once when Duncan MacLeod suffered a Dark Quickening and needed help, and once, after Alexa was put on life support in Geneva, he left her to attempt to find the Methuselah Stone in a desperate bid to save her life. The Stone was lost, however, and Methos hurried back to the Sacré Coeur Hospital in Geneva to find Alexa near death. He anointed her with myrrh, and climbed into the bed with her, where he held her throughout their last hours together.
He consider taking Alexa's body back to Santorini because she loved it there, but he didn't want her to be so far away, so returned to Paris and had her buried Montparnasse cemetery under the epitaph: Beloved.
Although she only appeared in one episode of Highlander: The Series, Timeless, her influence was felt throughout much of the fourth season and she was mentioned in the episode Deliverance, was central to the plot and Methos' motivation in Methuselah's Gift, and mourned in Through a Glass Darkly. She also appeared in the short story collection An Evening at Joe's. And she was mentioned in the short video, Highlander: Reunion, which took place many years after her death, wherein Methos had thought he would never feel again what he'd felt for Alexa, but was then contemplating marriage to a mortal woman, Julia.
Note: For details on Alexa's life and death with Methos see Postcards from Alexa.