Loosely based on FANTASTIC FOUR #37 (April 1965) by Stan Lee and Jack Kirby. The plotline of Sue seeking revenge for her father's death is dropped. In its place is added a subplot about Ben Grimm's birthday. There are scenes not in the original comic, including one of Morrat shooting at the wild game from his flying cruiser and later spying on the imprisoned FF through a portrait. Interestingly, Princess Allene is white and not green like all the other Skrulls, including her own father the emperor. The ending is also changed, Morrat lives and the FF receive a friendlier farewell than was found in the original comic book.