After the death of their mother, the Eun family hires a housekeeper that is emotionless and strictly obedient.

Eun Hangyeol discovers the truth about her mother's death and what caused it.

The children leave the house after finding out about their dad's affair.

The children kick their dad out of the house and force him to live in a hotel while Park Boknyeo takes care of them.

After receiving a letter saying that Boknyeo is a murderer, Eun Doogyeol tries to get to the bottom of it.

The other children want their dad to return but Hangyeol refuses to accept him.

The children invite Eun Sangcheol to come back home, but only on one condition.

Sangcheol tries to find out how to prove that he loves his kids.

The children make more attempts to find out about Boknyeo's past.

Boknyeo finally reveals the story of her past.

Outside forces stand in the way of Boknyeo becoming a part of the Eun family.

At the kids' request, Boknyeo agrees to become their new mother.

Yoon Songhwa, at the request of Boknyeo, does some investigation on Doyoung.

When a suddenly widowed father struggles to take care of his four children, the mysterious Boknyeo arrives to help out, and starts healing the family's broken relationships.

In lieu of soon getting married to Doyoung, Boknyeo becomes cold to the children to detach herself from them.

Boknyeo goes on a trip with Doyoung to her hometown with the suspicion that he is actually Seo Jihoon.

Boknyeo tries to bring Doyoung, who she believes to be Jihoon, to justice.

Boknyeo agrees to become their mom but in doing so, the children get something totally unexpected.

The Eun family asks Boknyeo for one last favor: to smile.