Actually, in One Hour of Freedom, from the Lion’s Zoo series, they were lovers before they were enemies.

She stopped by the window and turned to face him, the brighter lights in the bedchamber illuminating her face.  He traced the changes time had left. In London, when they first met, she had been more child than girl. In Spain, several years later, she was a girl hovering on the edge of womanhood. She was now fully a woman, and more beautiful than ever.

“I need to talk to you, Matthias.”

He sneered. “And you could not visit me in London? No, of course not, for undoubtedly you are involved in something illegal, and you know that in London I have the authority to arrest you.” A slightest exaggeration. His authority was limited to the river and the docks. But she wasn’t to know that.

She had learned to control her temper somewhere in the past four years. She did not react to his needling, but answered calmly, “I am being watched in London. I could not see a tail, but I may have been followed here, to Coventry. I cannot be seen to be talking to you.” She waved an expressive hand. “Hence the precautions.”

Despite himself, he was intrigued. No. He would not let her inveigle him again. “I have a way you can avoid that. Don’t talk to me. Go away, Electra.”

She sat in one of the two chairs by the hearth. “The Kingpin has ordered me to kill you,” she said, bluntly. “You are interfering with his trade, I am told.”

His hand had not left the gun in his pocket, but it had relaxed. No more. He hooked his finger back to the trigger, though every nerve in him jangled at the thought of sending a bullet into the flesh he had once loved so deeply.

The Kingpin was a shadowy figure that had, in the past couple of years, taken over some of the most lucrative illegal businesses in London. One of those was stealing cargoes from the ships in the Pool of London and the London docks, which put him in direct conflict with the Thames River Police. 

“I do not recommend that you try,” he growled.

She hooked a single eyebrow. “I have no intention of trying. But when I told the Kingpin that, he took someone very important to me. He tells me I have a choice. Kill you, or see the person I love die. I choose the third option. I have come to ask for your help.”

The sheer audacity of it silenced him for a moment, and then he swore, a long string of invective dredged up from the streets that birthed him. “You think I would lift a finger to help you save your lover?” he added. “Go to hell!”

“I undoubtedly will, for my sins,” Ellie agreed. “But first I must take down the Kingpin before he finds my daughter and carries out his threats against her, and I hope you will help me, for she is your daughter, too.”