The Grim Family, consisting out of Grim his wife Mandy and their children Grim Jr. and Minimandy were invited by the brother of Grim, Jack Skellington and his wife Sally. Mandy asked her children if they knew where holidays come from and said they better find out, and with that she motioned them inside the Halloween Tree towards Halloween Town, where they were happily welcomed with a song.
Halloween TownUncle Jack surprised his nephew and niece, which cause Grim Jr. to cry. Mandy said that Jack was their uncle and in an instant Minnie introduced herself to him. The Mayor stepped forwards and announced the start of Halloween and introduced their guests the Grim family.
Everyone headed inside to begin the party. Minnie was dancing with Jack which everyone admired and that she had much talent just like her uncle. And all that attention Minnie got, made Grim Jr. jealous. Sally noticed this and invited Grim Jr. to dance with her, Grim Jr. then showed his breakdancing skills which everyone found weird. Minnie then accidentely let Grim Jr. trip and let him fall into a bucket of water with apples. Everyone started laughing but stops when Jack says to.
Minnie tried to apologize for the accident she caused but Grim Jr. won't listen to her and walked away in anger and left the party. He went to the Guillotine Plaza and sat there on the fountain angry about what just happened. Suddenly the ghost dog Zero came to Junior and wanted to play with him, which cheered Junior somewhat up. Grim Jr. grabbed out one of his ribs and threw it away so Zero can return it. When Zero returned with the rib Junior suddenly got thrown in a bag and got kidnapped by Lock, Shock and Barrel who took him, inside of Bathtub to Oogie's Manor.
Grim Jr. was released by Lock, and was furious about them kidnapping him until the three kids explained that they wanted to become friends with him, diminished his anger. After Lock explained that putting people in a bag is an old habit of them and as a peace offering, Barrel came to offer some cookies. Junior got asked to join their club, to his surprise, but in order to join them he must tell them all about his family.