Nessa and Chase are on a star ship, Chase having picked up Nessa in space as her craft had hopelessly broken down (and for which no arrangements for retrevial / repair were made). Nessa has been deliberately infected with a species-specific Shielder virus, Chase is a bounty hunter. Bounty hunters have been indoctrinated and mindwashed so that once on the hunt, they don't stop until they have their prey. Any Shielder is on the hunt list, and unknown to Chase, a Shielder is what Nessa is. Trust issues all round as Nessa tries to get to a base where a cure might be found that she can then return triumpant to her hidden colony. The virus will activate in a month, shortly after which Nessa will die. And yet events conspire to keep them moving away from where Nessa needs to go. Will they make it there in time? Will Nessa confide in Chase? Will Chase trust Nessa as she continually seeks to leave the ship? Will Nessa's colony be saved?
Great characterisation of the two central characters, especially Nessa although Chase is well drawn too. Good secondary characters, particularly Sabin, although secondaries don't take up many pages. Of course, it was Nessa and Chase alone in a starship for a large part of the story.
However, Shielders and their powers were never fully explored - okay, they can shield their minds, but where's the threat in that? It's a very passive talent, and hardly threatening to the activities of others. Some ugly in-yer-face baddies, that hold the very real threat of incareration over the Shielders (in addition to having fashioned their specific virus, amongst others). But imprisonment can happen to any species, there seems to be nothing special about the power of shielding the mind that should justify their mistreatment, or indeed the bounty on their heads. Nessa herself never seems to specifically use this Shielding ability, although she can sense others of her kind.
Nessa has epilepsy and her colony of limited resources casts out the weak, so she's been living on the fringes for 10 years. Good device, and even more effective that Nessa's weakness easily treatable in more developed areas. I also found it completely believable that Nessa has absolutely no confidence in herself or her strengths (she doesn't think she has any) and for instance her hoarding of food when she's on Chase's ship, when scavenging is all she's done for the past 10 years, only added to the depth of impression of her character.
It irritated me how Nessa sought her parents approval right to the end, which given her courage and personal development through the book I would have prefered that she come to the realisation that she had worth in herself and didn't need the approval of her parents. Chase, her brother, her new friendships and the children could show here that she didn't need what she had needed at the start of the book - the acceptance of her home colony, who had mistreated her so. To me, this need for the approval of those who had neglected her was a weakness in the story. Even more so that Chase did not counter this with his own belief in her (if only through passively taking part in the return to Nessa's world). I guess the book would not have been truely concluded without the return to Nessa's colony, but still...
Overall, a very well written book, well paced with good characterisation, and the romance between Chase and Nessa was well developed indeed. I would have given it 5 stars if the plot had been thought out a little more as outlined above (especially, given the title, the Shielder abilities) but an enjoyable read nevertheless. I recommend it.