Once upon a time, after sun die moon never show up

"Once Upon A Time, After Sun Die Moon Never Show up". The story about one broken girl, and one arrogant, cold, CEO or said mafia leader. A flower girl, with a kind, soft heart, pretty face, personality just like her face beautiful, always smile, make other smile, cheer others, comfort other, happiness cover her life. Is it true? CEO of biggest and famous company, but good with once he loves, rude heartless, emotioness, no feelings in his body, hiding a secret. What is his secret? What happened when both meet?