you aren't my boyfriend

Kwon Chin-Hwa, the yogurt prince, is the son of two wealthy parents who own a successful yogurt company has been dating Geum Hana, for three years, they are said to be the it-couple by anyone who knows them, but it all goes downhill when Kwon Chin-wa asks Kang Huan for an odd favor, he has to text Geum Hana and pretend to be Kwon Chin-wa, her boyfriend.
That's weird.