That night, Danny sensed the presence of another Immortal, Damon Case, who challenged him to a duel. He wasn't ready to face Case, telling him he didn't even own a sword yet. He fled to Duncan's barge and told him about Case. Duncan had encountered Case before when Case had killed another new immortal, a student of MacLeod's.
Duncan tried to talk to Case about Danny, but Case was inflexible, immortals - no matter how young or inexperienced - were there to challenge and fight. Danny called the police in an effort to prevent Duncan from losing his head, interrupting the confrontation.
Duncan told Danny that he needed to train in Japan, but Danny couldn't leave his mother behind. He told MacLeod that he was offered a show in Las Vegas.
Later, Duncan faced Case. After a duel, Duncan held the advantage, and asked the man to walk away and leave Danny be, but when Case refused, Duncan took his head and received his Quickening.
After Case's death, Duncan visited Danny who asked him to help him in a trick. Danny cuffed Duncan and pulled out a sword. He nearly took Duncan's head, but Duncan got free of the cuffs. Danny had wanted to take Duncan's head so he would have the strength to defeat Damon Case, but Duncan told Danny that he had taken care of Case. Danny felt guilty for what he had planned to do.Danny took the booking in Las Vegas, and after doing his show, was last seen being threatened by Immortal Vrej Ratavoussian in the building's parking lot, while he was talking to his mother on a cell phone. Sensing the other, he told his mother that he loved her. According to the Watcher Chronicle (Highlander: The Series Season 4 Extras), Danny lost his head and his Quickening in that meeting.