The X-blade Express

(could-be canon for 'The X-blade Wielder' universe) It's Christmas Eve, and the Polar Express is fulfilling its duty of carrying lucky children to the North Pole. However, this year it has four additional passengers- none other than Sora, Riku, Kairi, and Heavyn! While Heavyn is happily living her childhood dream, will the others manage to survive all of the hijinks that ensue?