Back For Her Crown

Novalie Beaumont is a hard-working, smart, cold, hot-tempered badass assassin who listens to no one. She is the most feared assassin known as the "I Spy because she calls to play a game of eye spy and once she spots you better accept the fact you met your demise. She is also the rightful heir of the French, but her father killed her mother, remarried, and had her exiled and told her if she returned the whole mafia would be after her as he had them believe she was the one to kill her mother.
She has been running for years, but now she's no longer running from her past, she's is facing it and taking control of her destiny.

Aleksandr Sidorov is a cold, ruthless, smart, feared, and respected Mafia Boss.
He runs the Russian mafia, and people are afraid of him and wouldn't dare to try opposing him. No assassin tried to kill him and wouldn't even accept billions to kill him. No one dares to piss him off or look at him the wrong way in fear of their demise. That was until she tried and failed but didn't give up, which seemed to pique his interest and amuse him greatly.

What happens when she tries to kill him only to fail as he always seems to be steps ahead ? What happens when they realize they both want the same people dead?