What makes a hero? For years, Sienna Nealon has worked with the U.S. government to protect the world against other people with powers beyond those of a normal human. But after several clashes with the current administration, she finds herself with a new employer, an independent agency dedicated to helping stop threats to humanity. When a new hero and villain rise in New York City, Sienna can't help but get involved, even as the U.S. government sends its own response team, led by an old friend...and a new enemy. Soon, Sienna finds herself once more against the odds, against the government, ...

Sienna Nealon has dedicated her life to keeping those with powers from breaking the law at will. After years of filling a prison for the powered called the Cube, a Supreme Court decision opens the floodgates and lets all of them out again. Now Sienna finds herself going from hunter to hunted as the US government turns a blind eye while the former inmates target her and her friends for death. With the attacks hitting closer and closer to home, will Sienna be able to fight back against the overwhelming odds before she – or someone she cares about – gets killed?

Sienna Nealon has spent the last several years of her life working for the US government, policing people with powers beyond those of a normal human. Now she's come to the end of her government career, forced out by the powers that be...but not before she's called to Chicago to investigate one final murder. Then another. The deeper she gets into the investigation, the more mysteries Sienna unravels, and the more questions she's left with, until what began with a killing in an alley starts to look like a threat to the entire world...

For months, Sienna Nealon has been targeted by enemies that have hounded her at every turn, destroyed her reputation, and finally, struck at those dearest to her. Operating from the shadows, this mysterious group has never dared to show their faces in their quest for revenge against her. Until now. After crossing the final line, now her enemies have left themselves exposed for the first time, and Sienna will stop at nothing to drag them out into the daylight. Because while this may be her enemies' first time playing for vengeance, it certainly isn't Sienna's...

When Kat Forrest is nearly killed in Los Angeles by a man with powers and a mysterious grudge, Sienna Nealon doesn't think twice before coming to save the day. But as the threat grows nearer, old tensions between Sienna and Kat rise to the surface, and caught in the middle is Scott Byerly, a former flame of both of them. Will Sienna be able to put aside her grievances and save Kat from her attacker – and possibly herself – in time?

For months, Sienna Nealon has been targeted by enemies that have hounded her at every turn, destroyed her reputation, and finally, struck at those dearest to her. Operating from the shadows, this mysterious group has never dared to show their faces in their quest for revenge against her. Until now. After crossing the final line, now her enemies have left themselves exposed for the first time, and Sienna will stop at nothing to drag them out into the daylight. Because while this may be her enemies' first time playing for vengeance, it certainly isn't Sienna's...

When Kat Forrest is nearly killed in Los Angeles by a man with powers and a mysterious grudge, Sienna Nealon doesn't think twice before coming to save the day. But as the threat grows nearer, old tensions between Sienna and Kat rise to the surface, and caught in the middle is Scott Byerly, a former flame of both of them. Will Sienna be able to put aside her grievances and save Kat from her attacker – and possibly herself – in time?

Sienna Nealon has spent the last several years of her life working for the US government, policing people with powers beyond those of a normal human. Now she's come to the end of her government career, forced out by the powers that be...but not before she's called to Chicago to investigate one final murder. Then another. The deeper she gets into the investigation, the more mysteries Sienna unravels, and the more questions she's left with, until what began with a killing in an alley starts to look like a threat to the entire world...

Sienna Nealon has dedicated her life to keeping those with powers from breaking the law at will. After years of filling a prison for the powered called the Cube, a Supreme Court decision opens the floodgates and lets all of them out again. Now Sienna finds herself going from hunter to hunted as the US government turns a blind eye while the former inmates target her and her friends for death. With the attacks hitting closer and closer to home, will Sienna be able to fight back against the overwhelming odds before she – or someone she cares about – gets killed?

In a world of people with powers, Sienna Nealon has long been the one who maintained the order. But now she finds herself on the other end of the law, cast out and abandoned by her friends. On the run, hunted by relentless and implacable foes, she will face her greatest challenge – an enemy who holds a seat of power so great that even Sienna may not be able to stand up to him.