To earn money for your own living, you accepted to babysit the son of Yoo's family. Even so, this 'babysitting session' turns out as a mistake & misunderstanding when the one you should taking care of is neither a baby, a toddler nor a kid. It's an adult. A COMPLETE 28-YEARS-OLD ADULT. Is it just a mistake? Whatever it is, you've agreed to the terms and you can't reject it now, since the pay is quite large in amount. Now, taking care of Yoo Joonghyuk is your responsibility.