Her Billionaire Geek (Black Tie Billionaires #5)

When two billionaire executives agree to a temporary marriage — strictly for business purposes — while both are hiding an instant attraction and secretly plotting to make it a mutual thing… 
Architect genius, Greyson Maddox, is preparing to design a self-sustaining, futuristic house for a luxury homebuilder. When the builder’s daughter begs him to turn down the project, claiming it's just another one of her father’s doomed-to-fail schemes, he insists it's a good investment, then asks her on a date. For him, it’s love at first sight, but he doesn’t want to move too quickly and scare her away with his thousand and one geeky traits.

Though she knows better than to trust rich playboys, Milana Belmonte is wildly attracted to the shy and brilliant man working around the clock to help her father realize his biggest professional dreams. When she attempts to negotiate a huge discount for Greyson’s design services during their first date, he is quick to share the only way he’ll ever work that cheap — if they combine their extraordinary talent in a marriage of convenience for the duration of the project. A billionaire who’s skilled at calculating risks and returns, he’s totally banking on the odds that it’ll be just enough time to make her fall in love with him.