Before he met and befriended the other ghouls at Applegate Manor, friendly ghost Casper meets young Chris Carson, a lonely kid who decides to teach Casper how to be a proper ghost.
Kibosh, supreme ruler of all ghosts, decrees that casper must scare at least one person before Christmas Day so Casper visits Kriss, Massachusetts where he meets the Jollimore family and sets out to complete his mission. As usual, kindhearted Casper has a ghastky time trying to scare anyone; so The Ghostly Trio, fed up with his goody-boo-shoes behavior, secretly hires Casper's look-alike cousin Spooky to do the job-with hilarious results.
When Casper's been being friendly lately even when playing with a boy named Jimmy, Kibosh: The King of the Underworld has Casper enrolled into a Scare School headed by the two-headed headmaster Alder and Dash. He befriends Ra, a mummy with unraveling issues and Mantha, a zombie girl who keeps falling apart. When Casper discovers the two-headed headmaster's plot to use a petrification potion to turn Kibosh into stone and take over the Underworld and Deedstown, he and his new friends must stop him.
