Leather & Lark (The Ruinous Love Trilogy Book 2) by Brynne Weaver

Contract killer Lachlan Kane wants a quiet life working in his leather studio and forgetting all about his traumatic past. But when he botches a job for his boss’s biggest client, Lachlan knows he’ll never claw his way out of the underworld. At least, not until songbird Lark Montague offers him a deal: use his skills to hunt down a killer and she’ll find a way to secure his freedom. The catch? He has to marry her first. 
 
And they can’t stand each other. 
 
Indie singer-songwriter Lark is the sunshine and glitter that burns through every cloud and clings to every crevice that Lachlan Kane tries to hide inside. The surly older brother of her best friend’s soulmate, Lachlan thinks she’s just a privileged princess, but Lark has plenty of secrets hiding in the shadows of her bright light. With her formidable family in a tailspin and her best friend’s happiness on the line, she’s willing to make a vow to the man she’s determined to hate, no matter how tempting the broody assassin might be. 

As Lachlan and Lark navigate the dark world that binds them together, it becomes impossible to discern their fake marriage from a real one. But it’s not just familiar dangers that haunt them. 
There’s another phantom lurking on their doorstep. 

And this one has come for blood.