In the depths of the Tesera Mine, Oliver's hope of finding Tau again fades with each passing day. Just as despair consumes him, his Sentinel returns, only a shadow of the mighty being he once was.

Oliver swears revenge against those responsible, but there's no time to plan or savour being reunited, as a deadly mistake forces him and his friends to escape.

With no other choice, and a weakened Tau, Oliver traces the steps of his missing teammate to war-torn lands. He's wholly unprepared to discover the toll exacted by mining for magic, and it's worse than Oliver could have ever imagined. His hunger for revenge becomes a desperate need to put a stop to the atrocities committed, even if it means forming an alliance with an adversary.

In a sea teeming with horrors and growing distrust among his friends, Oliver and Tau find solace only in each other's embrace.