Cally O'Neal was trained from childhood as a premier killer. Officially listed as dead, for the past forty years she has lived a life of aliases, random lovers and targeted assassinations. This has led her to become the top in her profession, undefeatable, invulnerable. And in the process, she has lost her soul. Now she, and the man she loves, must battle to reclaim it. But Cally will find that leaving her dark world of shadow identities, murder-for-hire, and deadly secrets will be more difficult than any of the many lethal operations she carried out in the past. Her employers think she knows too much to live, and the scores of enemies she has made still have her at the top of their hit lists. The real question is, will she win her soul only to lose her life?

Cally O'Neal is officially dead. In her over forty years of being an active secret agent she hasn't used her real name, much less spoken to her sister. So when Michelle interrupts an important mission, by seemingly appearing out of thin air, it's an unexpected reunion. This highly anticipated sequel to the New York Times best seller Cally’s War features the return of Michelle O'Neal, the first human Sohon mentat. Sister Time is about life, love and covert operations amongst the universe's ultimate dysfunctional family.

Underground fighters Cally O'Neal and the O'Neal Bane Sidhe fight to overthrow Earth's tyrannical Darhel "allies," while Cally's father, Major General Michael O'Neal, battles to preserve that order in the hopes of preventing another invasion by the Posleen.