As winter falls on Eternia, all of Prince Adam and Princess Adora's friends from Eternia and Etheria have come together in the Royal Palace of Eternia, to celebrate the twins' first birthday together. Meanwhile, as Man-At-Arms tests out a new Sky Spy, Orko sneaks into the cockpit and accidentally blasts off into space, eventually crashlanding on Earth. Man-At-Arms manages to locate him and teleport him back, and Orko brings two lost Earth children, Miguel and Alicia, home with him. The children are worried about missing Christmas, which they had been ready to celebrate back on Earth, so Queen Marlena decides to introduce Christmas to Eternia and celebrate the twins' birthday with a Christmas party. But the presence of the spirit of Christmas on Eternia worries Horde Prime, who summons Hordak and Skeletor to his aid and sends them both to capture the children and put an end to the Christmas celebrations before goodwill spreads across Eternia...