Radio 7

Brian and Susan Ferguson are on honeymoon in Portugal. But the trip takes an odd turn when a stranger takes advantage of Brian leaving the dinner table to issue Susan with a warning - her life is in danger. The newcomer says she is 'the other Mrs Ferguson' (TOMF), leaves a note, and departs. When Brian returns he claims he's been watching Susan all the time, and she's been alone.

Susan meets TOMF at a bookshop called Ferguson's. TOMF says she 'was married to Brian for a very, very long time', but after his marriage to Susan. She claims he will kill Susan, then marry her and kill her. She aims to prove her credentials by predicting that Brian will later have a scar on his elbow, which comes true all too quickly due to an incident with some (Portuguese) sausages.

Susan returns to the bookshop, more credulous now. TOMF responds by saying that there is a very old book in the stockroom that will give them the answers they need. But Brian arrives and TOMF departs hastily. Brian is upset with Susan, and a Man intervenes, asking him to calm down. Brian sulks off, and the Man tells Susan not to trust TOMF, and that they need to get hold of the book.

Back in 16th century Portugal, Isabella awaits news of her husband, John, a protestant merchant, who she has betrayed to the Inquisition. Enrique, her manservant and lover, brings it - John is free and is even now at the door. There is a tense exchange between Isabella and John, who reveals that he did a deal with the 'Keepers of the Book'. Their help, he says, comes at a price, which must be paid off for centuries ahead. The book, he says is magic. It reveals the future, but it has also revealed Isabella's infidelity, and he kills her with a knife.

We return to the present day, and the Man and Susan break into the bookshop. The Man claims TOMF is a present day 'Keeper of the Book', a book which reveals futures that lead to suspicion and bloodshed. He says he is a descendant of Enrique, whose unborn child was also lost when Isabella was killed, and is sworn to destroy the Book. Apparently John was a Ferguson and the price John paid for his freedom was that Ferguson men would murder their wives. The Man and Susan descend into a basement, and from there into a labyrinth the book has apparently created to hide itself. Brian turns up unexpectedly and says a stranger has told him to kill Susan. The stranger has been appearing to Brian for years, urging him to marry Susan. Susan tries to talk him out of his murderous plan, but fails, and is killed in the same way that Isabella was all those years ago.

But it seems that Brian's arrival and actions were in fact a vision of the future revealed by the Book, which now traps the Man, and reveals itself to Susan alone. The Book tells Susan that it started life centuries previously as a peasant girl with the gift of seeing the future. Susan, the Book says, is special. Her future is uncertain, and she is the only one that can set The Book free. TOMF arrives and Susan says that she's worked out that she is actually Isabella, her soul given to the Book when she was murdered. TOMF (Isabella) says that Susan can set her free by giving her life in exchange.

Susan wonders why she's so special. Then, recalling her marriage, Susan realises that she had no family or friends at the ceremony. And no memories of before it either. Finding herself back in the bookshop with The Man, he explains that she has the power to move herself in that way. He was one of those who created her, from a 'cutting' from the spine of the Book. In fact she was the second attempt at such an experiment, the first having 'resisted' them, and stolen Susan from them. They must escape before the previous 'book' arrives. But it's too late. It's here. It's Brian.

Encouraged by the voices of the books in the bookshop, and The Book itself, Susan transports herself, The Man, Isabella and Brian home to London. But it's a London of her own devising. Buoyed up by Brian's renewed love for her, she uses her powers as a Book to rewrite the story, despatching Isabella and The Man and freeing the girl who was The Book. But this girl still has one more thing to ask of them.