Writing is a dangerous business. Edwin O'Donne, a neophyte novelist, has been increasingly forgetful, leaving his head in his writing after he is done with it. He no longer can be sure whether something happened in truth or only in his professional imagination, in some scene he had written. Into this prelude to insanity enters a mysterious, hedonistic woman who accosts his mind in the street, seducing him with philosophy. He comes to love her in but a few days. Yet how can he know she is real and not simply some character in one of his novels? Edwin fakes suicide and a coma to test her devotion. The real test, though, is of his own sanity.