Trailblazer by Michelle Diener

He’s on a mission . . .
She’s running for her life . . .
And if they get off-planet alive, she’ll have to trust he won’t reveal her darkest secret.
Tally Riva is not what she seems, and even she’s not happy about it. Infected, invaded, she’s not quite sure how to describe it, but on a disastrous mission to a ghost ship, something burrowed its way into her body. Into her mind.
When her commander decides the best cure for what he thinks is Tally’s trauma is to send her on the famous Veltos Trail, Tally goes without revealing what’s really behind her mental anguish. Anything to be seen as normal again, anything to ignore what she’s afraid is happening to her.
But Veltos isn’t the safe place it seems. The chosen military personnel lucky enough to be offered the chance to walk the Trail are supposed to be the only people on Veltos. But Ben Guthrie, a captain in Arkhoran Special Forces, knows they’re not. He and his team have been on Veltos for a month already, tracking suspicious enemy activity, and he’s gone undercover on the Trail in search of a satellite his superiors are sure has been shot down.
When Ben’s worst fears become reality, and they find themselves hunted by a cunning enemy through the thick forests of Veltos, Tally and Ben fight together to survive. And Tally has to decide if accepting the changes inside her will save them both, or be her doom.