Freed By the Cyborg by Alyse Anders

A protective cyborg must trust his mate to free his heart.

Ingo is the ice-cold head of security at The Prison. Feared by all, he rarely speaks as he patrols the corridors keeping both prisoners and the guards in line. When he’s told that he has a mate who’s traveled across the galaxy to be with him, he knows she will be nothing but trouble.
Darby didn’t have much time to think about her reasons for leaving Earth – not with the police hot on her trail. But waking up on a new planet and being told that the cyborg unconscious on the floor beside her is her mate – oh and he’s the chief of security of a prison, well that’s not so good for her.
When the prison goes into lockdown, Ingo puts his heart on the line and his trust in Darby, so they can save the lives of their friends in danger.