In Don't Toy with My Heart, Mr. Billionaire movie, adult toy designer Holly is forced to sign a contract marriage with arms dealer Derek after her company’s cash flow collapses. What begins as a simple exchange of interests spirals out of control as they move in together and face escalating crises. Derek is cold, dominant, and in total control, yet he begins to waver in the face of Holly’s resilience and kindness. Holly appears soft on the surface, but she grows stronger with every scheme, betrayal, and wound, learning to fight back. Caught between desire and genuine emotion, they move from using each other to saving each other, confirming their feelings through danger and misunderstanding, and ultimately breaking the contract to choose real love.