Misery by William Goldman

When romance novelist Paul Sheldon is injured and stranded by a car accident, his biggest fan, Annie Wilkes, comes to his rescue. What begins as heroism, however, soon turns into terror as Paul finds himself held captive by the unhinged Annie, who forces him to write a new novel featuring her favorite character. Based on the novel by master of horror Stephen King and adapted for the stage by William Goldman, author of The Princess Bride, Misery gives a new meaning to the idea of writing like your life depends on it.