First there was darkness...Alessa Spiteri survives a bombing incident on the London Underground only to discover that the horror she experienced there is only the beginning of the nightmare.As she struggles to rebuild her life, she finds herself haunted by grotesque, shadow creatures - monsters Alessa believes are hallucinations, born of her traumatised mind until she meets Casey, also the survivor of an Underground bombing, who tells her she can see the monsters too.Together, the women plan their fightback against the creatures, a course of action which takes Alessa back into the tunnels beneath the city.Back into the darkness.