Overview: Izzy and her father attempt to stop the war in heaven enveloping the earth, an effort which fails due to Izzy's refusal to sacrifice Jinx. Holly, determined to exact her revenge, releases one of the first gods, known as the Shining Ones. Dylan and Silver struggle to find a way to free him from her fatal spell, just when she needs him the most. In the power vacuum left by Holly's defeat, the Sidhe jockey for position and the angels, outraged that Izzy gave the spark to Azazel and the demons, threaten to break off the truce that has lasted millennia. The war in heaven threatens to return to the earth. Holly seeks revenge by calling up Crom Dubh, one of three early gods called the Shining Ones. She targets Izzy, Jinx and all those she believes betrayed her. Meanwhile, Silver is elected the new leader of Holly's people, much against her will.
She wants to find a cure for Dylan, a way to free him, and has never wanted to lead. Amadán is pulling strings to manipulate the situation, and the Magpies start to follow Jinx and Izzy. Amadán wants Jinx to serve him, in order to get access to Izzy. The angels blame Izzy for Crom's release and refuse to help her as they helped previous Grigori against the early gods. She must do this alone. The other realms are caught up in their escalating war, and only Izzy and Jinx seem to realise that Crom Dubh is a real threat. Izzy must retrieve the sword of light from its keeper Donn, the lord of the Dead, and travels to his hollow, facing many painful truths about herself and her situation. Jinx follows her, feeling her slipping further away from him as their quest progresses.
But the sword is not the only thing that could help. Dagda's harp is just as powerful, but the harp is lost. Izzy claims the sword, unaware of its corrupting influence on her. It will leech away the goodness in her, leaving her an empty shell. Izzy is tricked by Holly into believing that Jinx has betrayed and deserted her. She leaves Jinx in the realm of Donn where he barters for his release. Azazel claims her as his creation and promises that he will win this war. He tries to take the sword which would give him victory.
Izzy manages to stop Azazel taking the sword and drives Crom Dubh and Holly away from her family. As her father tries to broker peace in a rapidly deteriorating situation, Izzy finds herself blamed, and alone with Amadán and the Magpies, who offer to protect her. She agrees, believing Jinx gone forever, and that she has betrayed him. Jinx arrives too late to stop her and is captured by Holly.