With only a couple minutes' warning, an alien attack on Justiss Kaye's home planet leaves her being the lone survivor and plagued with nightmares. Somehow she is rescued, but she has no memory of who or how. Joining the planetary military, her plan is to rise in the ranks and get revenge on those that attacked her, destroyed her home, and killed everyone she knew.

She dreams of becoming a Legionnaire, an elite class of warriors, but she keeps getting passed over for promotions at her own base regardless of how good her numbers are. She's one of the best and she knows it. When she's passed over for a third time, she demands to know why, knowing her superiors don't like being questioned. There's more than her job on the line, it's her life.

Little does she know that she's been watched for a while and her dream is about to come true. After being rescued yet again, she's put to the test and finds herself being invited to become the third in a Legionnaire triad. And then the fun really begins. They find evidence of the fleet that attacked her planet and many others, and it's now their mission to save as many other planets as they can.

Justiss is her name for a reason, and she won't rest until she's served up her own brand of retribution.