Wonwoo Jeon one of the Owner of RQS Company.
Has twelve brothers who runs their company. They all called 'the kings of serenity'.
A wealthy boys, they even don't have to move a single pen to work hard on.
A young architecture student, Kim Nara, damages the bike of Choi Seungcheol, who is the son of a rich, influential businessman. Unable to pay for the damage she caused, he makes her sign an agreement for her to work for him as his slave for 72 days.
And so their story starts.