When does Danny Phantom return?

Danny Phantom is an American animated paranormal superhero action adventure television series. The series premiered on April 3, 2004, immediately after the 2004 Kids' Choice Awards, and ended on August 24, 2007. It follows Danny Fenton, a teenage boy who, after an accident with an unpredictable portal between the human world and the "Ghost Zone", becomes a human-ghost hybrid. Danny is aided in his quest by his two best friends, Sam Manson and Tucker Foley, and his older sister Jazz.
Daniel "Danny" Fenton, a 14-year-old boy living in the small town of Amity Park, lives with his ghost hunting eccentric parents, Jack and Madeline "Maddie" and his overprotective sister, Jasmine "Jazz" The Fentons' Ghost Portal was created by his parents in their attempt to bridge the human world and the Ghost Zone (the parallel universe in which ghosts reside), failed to work. Once inside, he inadvertently presses the "On" button (which his parents naively failed to do), thus activating the Portal and infusing his DNA with ectoplasm, transforming him into a half-ghost. Danny is initially frightened by his new abilities.