When the festive season arrives at Larklight, so does some unsettling news. A sinister-looking cloud is fast approaching the outskirts of the Known Universe. The closest planet, Georgium Sidus, has but two human inhabitants: the missionary Rev. Cruet and his daughter Charity. Their most recent communication read: 'Great danger - imperative that'. And so, aboard a Naval gunship, Art, Myrtle and family bravely go where only one man and his daughter have gone before, to determine the nature of the menacing cloud and rescue the Cruets.