Robert is determined to rescue Lorn, who remains trapped in the tiny underground world from which he has managed to escape.

She'll die if he doesn't help her. But Lorn doesn't know what danger she is in. Something is drawing her to the dark tunnels underneath her world.

Is it something that is calling her home or something more sinister?

Can Robert get to her before whatever lurks in the black room does?

Gillian Cross is one of the UK's top children's authors, and has won a host of major prizes, including the Carnegie Medal, the Whitbread Award, and the Smarties Prize.