Halo: Lone Wolf (Halo: Lone Wolf #2)

With Dr. Chen, a dangerous ex-ONI scientist, in her sights, Spartan Linda-058 and her AI companion must find a way to end the threat posed by Chen and evacuate the endangered humans in the settlement. But as the Covenant prepare to stage an assault, Linda discovers that Chen holds the key to a secret that could endanger all of humanity if it fell into the wrong hands.