Cyborg Rider by Honey Phillips

Can a lonely cyborg protect a determined scientist from the dangers of Mars?

Dr. Sadie Tucker has spent her entire life in the pursuit of knowledge. That quest takes her to the wild Martian frontier, where her latest bioengineering project could revolutionize homesteading on the planet. She can’t afford any distractions – even though the big, silent cyborg ranger guarding her reminds her that she is a woman as well as a scientist.
When the military sent Z-384 to Mars, he put his troubled past – and his humanity – behind him. He knows that only cold, isolation, and work lie ahead. But the intriguing little scientist he’s assigned to protect suddenly has him longing for a different kind of future.
When Sadie and Zeb are trapped in a mysterious underground chamber, any kind of future seems impossible. With some unexpected help from Sadie’s prototype, can the two find a way to escape? And if they do, can they find happiness together?