How many versions of the truth can there be?

In June 2014, Julia White - a beautiful and intelligent young woman - blows up a coffee shop in central London, killing twenty-four people before turning herself in to the police. Apart from publishing a potentially ironic manifesto, she refuses to explain the reasons for her actions.

Clare Hardenberg, an investigative journalist, has been commissioned to write a biography of Julia but at the start of the novel she is on her way to prison herself. What has brought her to this point?