It is a sunny afternoon in April 1910, on the verge of Samuel Clemens' 75th birthday, when Harold Atwater, a young publishing representative, comes to persuade the old writer to start a new novel in the vein of Tom Sawyer and Huckleberry Finn. Twain refuses, claiming his humor has been used up and that he's forgotten all about boyhood,and furthermore is determined to "hooky out of this world" by the approaching light of Halley's comet, which last appeared in the sky on the night he was born. But then his interest is piqued by a mysterious teenager who lurks about the house, examining furnishings and filching cigars and sandwiches. Is the young hoodlum real? Eventually Twain traps the boy into conversation and comes to understand at least one 20th-century youngster. He teases information out of the boy and manages to influence his future. Then Twain decides to take a trip back to his old Missouri haunts to refresh his memory enough to,maybe,create a fictional youth, counterpart to the boys he knew long ago. At this point, Halley's comet,brilliant in the sky overhead--interrupts his plans. Two recognizable boys tumble in through the window and yell: "Hurry, Sam! Aren't you ready yet? We've got our raft ready and we're going to all the watery places. M-a-r-k three! Quarter-less-three! Half twain! Quarter twain! M-a-r-k twain! M-a-r-k twain!",then the sound of a steamboat whistle and the surge of a calliope. One int. set.