

Well, it refers to novelist Erin Kelly's psychological thriller, which this has been adapted from, of course. Perhaps I missed it, but I don't think we know what The Poison Tree refers to yet. There are things, outlines, sketches (is Biba still alive? Did she do it? Did Karen do it? Do we even know what "it" is?) that you can guess at but won't become clear until next week's conclusion. The picture is slowly filled in – from both sides, then and now. The past, and the dark secrets it holds, don't seem to want to go away. Or can they? There are mysterious phone calls. Here, with the sound of the waves on the steep shingle, they can forget the past and get on with their lives …

So it's back in the Volvo and off to Dungeness on the Kent coast, which is up there with the north Norfolk coast as one of TV drama's favourite film locations.

That was all then, though, and this is now. And for Biba's nearly-as-irritating-as-she-is, fake-gangster boyfriend who was shot moments later. Things came back to ground with a bump, literally for Rex and Biba's dad who fell – or was pushed (but by whom?) – down the stairwell. Smiley faces and 50 shades of bright, bright colours.īut, like so much in the 90s, it went wrong. They spent a happy summer together, a summer of love and beaujolais nouveau and pilled-up hedonism. Karen was seduced by Biba – glamorous, arty-farty and deeply annoying (I'm definitely not a Beliba) – and Rex, by their bohemian lifestyle. It was here, in the 1990s, that Karen, an innocent student from Warrington, first became involved with Rex and his sister Biba. Something bad happened, on the staircase you can tell by the echoes. As they're passing through Highgate (funny route), they stop off at the old house for some echoey flashbacks.
