A fast writer, Semple completed a forty-page outline within a few days and delivered it in August 1975. While De Laurentiis was pleased with Semple's outline, he expressed displeasure with the Vatican Library subplot, which was immediately dropped. It would later be replaced with Petrox discovering the island through obtained classified photos taken by a United States spy satellite. Within a month, the 140-page first draft incorporated the character of Dwan (who according to the script was originally named Dawn until she switched the two middle letters to make it more memorable), the updated rendition of Ann Darrow from the 1933 film. For its second draft, the script was reduced to 110 pages. The final draft was completed by December 1975.