Yogi and Boo Boo usually snooze right through Christmas. (Hibernation, you know.) But this year, happy holiday music rouses them from their sleep and right into the fun: skating, skiing, singing and trimming the tree. But life isn't all mistletoe and eggnog. Two holiday grouches - a mysterious hermit and the obnoxious nephew of Jellystone Lodge's owner - are determined to ruin Christmas. And our two heroes, joined by Snagglepuss, Augie Doggie, Doggie Daddy, Huckleberry Hound and more Hanna-Barbera favorites, are just as determined to make December 25 the jolliest day of the year