While on an away mission in 2366 to study the homeworld of the now extinct Koinonians, his mother was killed by an undetected explosive device leftover from the Koinonian Wars. Worf felt personally responsible for her death, since he was the leader of the away team. Jeremy blamed Worf and ultimately vented his anger that Worf was alive rather than his mother.
A second non-corporeal species of Koinonians, unknown to the crew of the Enterprise-D, sensed Jeremy's pain and created a replica of his mother. This replica appeared on the Enterprise-D and attempted to take Jeremy back to live on the planet to keep him from suffering the loss of his mother. When Worf discovered Lt. Aster's impostor, she vanished. She later reappeared and transformed Jeremy's room into his home on Earth. Jeremy became confused, and at first wanted to leave with the being, believing that it was his mother. Wesley Crusher, who had lost his father when he was young, with the help of Deanna Troi, Captain Picard and Worf, helped persuade Jeremy to accept his mother's death. In so doing, the Koinonians were convinced that Jeremy's true happiness rested with his fellow Humans and disappeared.