"An Hourly Barnyard Phantom Adventure" is a one-hour special in Season 4 about a crossover between Danny Phantom and Back at the Barnyard. The film is the fifth in Danny Phantom and the second in Back at the Barnyard.
The story begins with Dan Phantom in the Ghost Zone looking for Danny Fenton. When he tried to search for him, he was confronted by the venus flytrap-like ghost. It tried to eat him, but he beat it up. In Fenton Works from Amity Park, Danny Fenton's dad, Jack Fenton, made a Fenton Teleporter. In the barn from Oedeville, Otis the Cow is rounding up a party. Then, he suddenly heard Snotty Boy knocking on the door, so the cow tells the animals to make the barn back to normal. Snotty Boy tells Otis that he will make ghost potion to drink, so the world, as he knows it, is about to end. Back in Fenton Works, Danny uses the Fenton Teleporter, and he ends up in Oedeville, whilst Otis and Pip end up in Amity Park.
When Danny enters the barn, he is surprised by the animals, except Otis and Pip. They are rounding up a congratulations party for Danny that he is the first half-ghost boy to join the barn. Back in Amity Park, when Otis and Pip go upstairs, Jack, Maddie and Jazz Fenton told them that it's time to get some lunch at Nasty Burger. Jack gets food at the Nasty Burger drive-thru. Then, he gets home after Nasty Burger closes. When Otis and Pip goes to Danny's house, they see Dan Phantom disguised as Danny Fenton. He tries to attack Otis, Pip, and the Fenton family (except Danny), but Otis squirts milk at him, so Dan Phantom runs away for the grand opening of Phantom Bell.
Back in Oedeville, Danny and the barn animals (excluding Otis and Pip) go to GameVille for the Zbox One. When Danny gets the Zbox One with his ghost powers, the police arrives, and they try to arrest them, but he uses his ghost powers, causing the police to go unconscious. In Fenton Works, when Otis and Pip make comic books about Cowman and Ratboy stopping Dan Phantom from evil (in which Otis is the writer while Pip is the illustrator), Tucker and Sam arrive and tell them what they are making. Otis and Pip told the twins that the animals are making "The Misadventures of Cowman and Ratboy". After they make their comics, they walk up into Nasty Burger, but it was replaced by Phantom Bell, so Otis and Pip decide to spy on Dan Phantom (who is considered Phantom Bell's boss) and tell him to replace Phantom Bell back with Nasty Burger, and when Dan decides not to, he gave chase to Otis and Pip, and Otis squirts milk at Dan Phantom once again, leading Dan to plan on plotting to turn all Amity Park residents into his slaves with the exception of Danny Phantom, who is still in Oedeville.