This week, two and a half months after Natalie Wood's body was found floating off Catalina Island, MGM will resume shooting her unfinished last film, the $15 million sci-fi thriller Brainstorm. But whether the movie will ever reach the screen remains as uncertain as the circumstances that surround the 43-year-old star's death by drowning last Nov. 29. While the full story of that night may never be known, the tragedy has sparked an epic high-stakes corporate battle.

Stunned by Wood's death, MGM decided to scrap Brainstorm and cashiered the cast and crew, including Natalie's co-stars Christopher Walken, Cliff Robertson and Louise Fletcher. Simultaneously the studio prepared to file a claim with Lloyd's of London, the principal underwriter of a $15 million insurance policy on the film. MGM executives said that several of Natalie's major scenes remained to be shot and declared the film unsalvageable. Elsewhere the suspicion lingered that the studio, which had made huge investments last year in a takeover of United Artists and in memorable box office duds like Pennies From Heaven and Buddy, Buddy, was simply cutting its losses.

Lloyd's had a claims adjuster look at the film already shot, some of it edited, then decided to put up $3 million to finish the movie rather than pay off. Some time next month MGM will decide whether to add the special effects that would allow the film to be released or file a formal claim for losses.

In the movie, Walken plays a research scientist who devises a machine capable of transmitting one person's thoughts to another. To save Brainstorm, Lloyd's is gambling on the talents of its director, Douglas Trumbull, 39, a Los Angeles-born special effects whiz, famed in the film industry for his work on 2001 and Close Encounters of the Third Kind. Trumbull is confident that Brainstorm can be completed and is bewildered that MGM brass didn't consult him before abandoning the project. "No one even came to the cutting room," he protests.

Trumbull says he told Lloyd's what he told MGM after Wood's death: Natalie had completed all her key scenes two days before she drowned. There will be no need to do what the studio did in 1937, when Jean Harlow died of uremic poisoning while filming Saratoga with Clark Gable. Harlow was replaced by a stand-in whose efforts to hide her face from the camera were laughably obvious. Vows Trumbull: "We won't use any fake Natalies in floppy hats." Instead, he has cut two scenes that were to have taken place between Walken and Natalie, who plays his estranged wife. Other sequences involving Wood have been rewritten.

If MGM refuses to release Brainstorm after the new scenes are completed, the result could be prolonged litigation. That might leave the film shelved forever—a prospect that horrifies Trumbull. "I think Natalie really grew up in this film," he says. "She looks like a woman here, not an ingenue anymore." Cliff Robertson agrees. "Natalie was very happy with the picture," he says. "I think she would have been the first to say go ahead and do it."

As for Wood's widower, Robert Wagner, he has declined to view any footage from Brainstorm since his wife's death. During the Christmas holidays he went skiing in Switzerland with his daughter, Kate, 17 (whose mother is actress Marion Marshall), Natalie's daughter, Natasha, 11 (whose father is producer Richard Gregson), and his and Natalie's daughter, Courtney, 7. Back in L.A. a week ago, the girls joined Dad at a promotional softball game for the American Heart Association, hosted by the cast of his TV show, Hart to Hart. He has apparently decided to try to adjust to his grief and get on with his life. "I can't very well tell my children to go to school," he reportedly explained to a friend, "while I sit locked in my bedroom crying."