His Little Kitten. The Training Kennel Files, #5

Julie was the untouchable heiress, raised in marble halls and taught to smile while powerful men decided her future. One spilled glass of champagne changed everything. Trevor was never supposed to be in that ballroom. Younger, dangerously charming, and completely uninterested in her father's empire, he saw right through her perfect mask and decided she belonged to him the moment their eyes met. What started as a reckless escape became something darker, sweeter, and far more possessive.
Behind closed doors, the spoiled princess kneels and calls him Master. In secret neon-lit rooms, she becomes his Kitten: cuffed, breathless, and beautifully obedient. He gives the commands she's secretly craved her whole life.