It is late at night on a notorious council estate in east London. A van - garishly painted with a grinning clown's face on the side - is being driven erratically. When the police pull over the driver to question him, they discover, inside the van, the body of a young woman.

A murder suspect . . . an arrest . . . a confession . . . A case done and dusted? But their suspect claims his victim is not his first, but his third.

Five years earlier, a 13-year-old girl disappeared in broad daylight on a busy London street. DCS James Langton headed the investigation and left no stone unturned. The fact that case was not solved has haunted him ever since. The enquiry has opened up again but, unable to lead it due to ill health, Langton brings in DCI Anna Travis. Meanwhile the murder team begins the laborious task of verifying the details of the confessions and uncovering the identity of the second victim.

And then the suspect changes his story. They know they have a murderer in custody - but is he a serial killer or just a compulsive liar?