S1, E4: The murder trial continues, with Costley's lawyer, Bonnard, hingeing her defence on the claim that Costley suffers from a personality disorder, which would have impeded his ability to react normally during an altercation with Selway. However this theory is ripped apart by the prosecution barrister, Price, and Costley's case seems to be left in tatters. Yvonne finally takes the stand. She sticks firmly to the story, and confidently holds her own. When she moves on to talk about the rape, her evident distress and the authenticity of her account awaken sympathy in the jury. However, Bonnard and Costley aren't finished yet. After a catch-up initiated by Costley, Bonnard asks Yvonne about working at the Beaufort Institute, and her intimacy with that part of Central London - the surrounding cafes, shops, streets and side-streets - specifically a small alley called Apple Tree Yard. Yvonne's heartbeat quickens and time slows down, as Bonnard goes on to describe the backstreet where Yvonne had sex with her lover, Mark Costley, just before going to the party where she was attacked by George Selway. Bonnard is triumphant - Yvonne is a liar. She was having an affair with Mark Costley; and she goaded her lover into killing the man who allegedly attacked her. Costley has reneged on their agreement, and Yvonne's darkest secrets are public property. Her liberty rests in the hands of the jury. But whatever the verdict, her good behaviour now has to last a lifetime.