A woman James Kirk loved during an earlier retirement from Starfleet and left to return to duty, whose mountain home he finds himself back in when the Nexus claims him in Star Trek Generations.
Antonia was the partner of James Kirk during a period, some years before 2293, when he had left Starfleet and was living in the mountains. He walked away from her to go back to the service, and came to regret it.
In Star Trek Generations the Nexus returns Kirk to the morning he told her he was leaving. Picard finds him chopping wood and cooking her breakfast, determined this time to stay, and then riding out to meet her at his uncle's barn in Idaho on the day they first met, ready to propose.
Antonia herself is seen only as a distant figure on horseback. When a jump on his horse brings no fear, Kirk realises that nothing there is real, and agrees to leave with Picard for Veridian III.