Brutal Prince (Brutal Birthright, #1) by Sophie Lark

They're a match made in Hell.

The Griffins and the Gallos have been battling for control of Chicago's underworld for generations. Their rivalry has always been flammable, but it reignites with a fury when Aida, the youngest and wildest Gallo sibling, crashes a party at the Griffin mansion and accidentally sets fire to the library. To stave off all-out war, her father quickly arranges a marriage between her and Callum Griffin, eldest son and heir to the Irish mafia.

Cold, ambitious, and brutal, Callum is determined to tame his headstrong new bride. But Aida is more than capable of giving as good as she gets—starting with poisoning Callum on their wedding night. The problem is, murdering him would be a lot easier if he didn't look so good while she was trying to do it.

She's got a lockbox around her heart. He's got something to prove.

In their struggle for dominance, who will go up in flames first?