The Billionaire's Contract (On Call for the Billionaire #6)
Celia Sykes

Meanwhile, she can't help but notice Jackson is up to something. He's taking phone calls at all hours, he's hiding documents from her. Just as she's about to sacrifice everything to save him, Amy wonders if she can ever fully trust Jackson Blake.
When he finally does reveal what he's been up to, how will Amy respond? This 7900 word story is the final part of the On Call for the Billionaire series. I recommend starting with Part 1 of On Call for the Billionaire, "Caught and Punished."