A girl's body lies, posed, on the pale sand of a Hamburg beach, a message concealed in her hand. 'I have been underground, and now it is time for me to return home...'

Jan Fabel, of the Hamburg murder squad, struggles to interpret the twisted imagery of a dark and brutal mind. Four days later, a man and a woman are found deep in woodland, their throats slashed deep and wide, the names 'Hansel' and 'Gretel', in the same, tiny, obsessively neat writing, rolled tight and pressed into their hands.

As it becomes clear that each new crime is a grisly reference to folk stories collected almost two hundred years ago by the Brothers Grimm, the hunt is on for a serial killer who is exploring our darkest, most fundamental fears. A predator who kills and then disappears into the shadows.

A monster we all learned to fear in childhood.