There follows efforts by Ferrell to determine whether he's going mad (Tom Hulce as psychiatrist) and to get answers from a "literature expert" (Dustin Hoffman), while falling in love -- as dictated or explained by the voice -- with Maggie Gyllenhaal's baker, whom he is supposed to be auditing. Meanwhile, over in the B - or possibly C - story, Thompson's publishers are worried about her missing her deadline, and have sent over Queen Latifah to get over her writer's block.
It's a nice romcom in a way, though strangely I spent most of the film watching Gyllenhaal's face and wishing she'd been cast as Adama instead of Natalie Portman, but the problem is that this film is the difference between good sf and bad sf - or, perhaps, between written sf and movie sf - since the approach of the film has to change radically when Ferrell manages to meet with Thompson, who then has to recognise that she's writing - and writing off - a real person. In movie world, this becomes the point where the status quo has to be restored, or at least the unusual situation has to be removed. In written sf, it's the end of, say, chapter three, and is the point where the author really gets going. After all, Gyllenhaal's a character in the story too, and apparently subject to mind control - or at least invasion of privacy.
The performances of the four main characters are excellent, incidentally; Thompson and Hoffman are (always) a joy to watch, and Ferrell and Gyllenhaal are entertaining enough. But the story's unsatisfying. Once author and character meet, there's no doubt how this story is going to pan out, which is a pity given that early scenes note that to do so would ruin the tale.