Devil May Care by Christine Pope

Love is about to go through Hell…literally.

Real estate agent Delia Dunne thought house flipping with her quarter-demon boyfriend would be her biggest challenge. She was wrong. When a wedding invitation leads them to investigate a suspicious chapel, they uncover a demonic conspiracy that makes their previous supernatural encounters look like warm-up acts.
Caleb Lockwood’s demon heritage has always been a source of conflict, but now it’s putting everyone he cares about in danger. Vinea, an Earl of Hell, is orchestrating the ultimate hostile takeover: turning Las Vegas into a permanent gateway between Earth and the underworld. And he needs Caleb’s unique bloodline to make it work.
With shell corporations mysteriously buying up prime real estate along ancient ley lines, coordinated “accidents” shutting down competing venues, and Delia’s psychic abilities exploding beyond anything she’s experienced before, the clock is ticking toward May 30th — the day a celestial alignment will give Vinea the power to rewrite reality itself.

Assisted by half-angel Ty Carter and private detective Pru Nelson, Caleb and Delia must navigate family drama, supernatural politics, and their own deepening bond while racing to prevent millions of demons from turning Earth into their new home. But when Vinea makes it personal, threatening everyone from Delia’s cousin to the entire city, she and Caleb will discover that sometimes the most powerful weapon against Hell is something Heaven and the underworld both underestimate: love that refuses to quit.

In Vegas, you can bet on anything — except the house always winning when the stakes are eternal.