1x4 - Highlander: The Animated Series

After encountering a burning water called oil, Ramirez and Quentin try to visit a Jettator named Errol who knows all the secrets of the Earth. They instead find a tortured and demented soul named Melvyn who thinks he is an Immortal. Making things worse Quentin's sister Clyde looks like Melvyn's daughter, whom he believed to have perished at the hands of Kortan's Hunters.