Chae Gyeong meets with the Queen to express her thoughts on her arranged marriage. She uses modern slang terms that completely confuse the Queen and leaves a bad first impression on her. Chae Gyeong sees the photo of her fat self in the newspapers and cries. Chae Gyeong stands before dozens of reporters with puffy eyes from a lack of sleep. Yul happens to see a photo of Shin and Hyo Rin in her phone. The Queen Dowager is delighted to see Yul back from England. Shin claims that he will not allow the woman he loves to live like a doll in the Palace. Being chased for wearing her uniform incorrectly, Chae Gyeong runs into Yul at school. Yul is curious about the girl that Shin is going to marry. The Queen is anxious about Yul, also called Prince Ui Seong, returning from England. Chae Gyeong leaves her house to enter the Palace...

Lessons for becoming a proper Crown Princess began as soon as she enters the Palace. She has to endure hard training, which includes learning proper Palace etiquette, memorizing the entire wedding process, with the Prince showing neither interest nor offering any help to her. Life in the palace is not easy, even from day one. A huge ceremony is held to welcome the new Crown Princess, and with the entire country watching, Shin and Chae Gyeong are wed in the traditional 21st century Royal Procedure. Meanwhile, Hyo Rin, who rejected Shin's proposal, is standing on a ballet stage in Thailand.

He wants to ensure that they receive what is promised to them for agreeing to the marriage. While Shin is being very serious, Chae Gyeong, is busy enjoying the privileges of being the Crown Princess and slowly adapting to life as a member of the Royal Family. Chae Gyeong and Shin go to school but Chae Gyeong is treated like an outcast with the only person that actually talks to her being Yul. Shin bumps into Hyo Rin, who has just returned from her contest.

Yul, a transfer student in her class, turns out to be Prince Ui Seong. At first, Chae Gyeong has a hard time adjusting to life in the palace with its strict education and rules, but thanks to the warmth of the King and other Royal Family members, she begins to find the attractions of the Palace culture. Meanwhile, Hwa Yeong prepares to open a yoga center while plotting with Mr. Choi against the other Royal Family members. Yul becomes closer to Chae Gyeong and her friends. Prince Shin's birthday is coming up soon and Chae Gyeong is getting excited about the birthday party but the only people awaiting her are Hyo Rin and Shin's friends, who despise her.

After attending a number of events with Shin, she is loved by the public for her common looks and free spirit. Yul advises her to carry herself with dignity. At the opening of the yoga center, Hwa Yeong meets Hyo Rin and discovers that she is the Crown Prince's ex-girlfriend. The Queen discovers that Hwa Yeong secretly came to Korea and has opened a yoga center, and is greatly displeased. Meanwhile, at the Palace, a party is held to announce the officially married Crowned Prince and his wife to the ambassadors of the constitutional monarchy...

Hyo Rin recalls the good old days with Shin and remembers what Hwa Yeong told her and sets her heart to win Shin back. Meanwhile, Chae Gyeong misses her family because she has not seen them since she moved into the Palace. But soon, she and the Prince are finally allowed to go visit her family. Chae Gyeong is very happy to be home, but Shin has a hard time adjusting, due to the fact that he has lived his whole life in the Palace. Chae Gyeong's family also feels uncomfortable being in the same house with him. Chae Gyeong and Shin, who often quarrel, end up spending the night together in Chae Gyeong's small room.

Different to Chae Gyeong's happy and close-knit family, the King is strictness personified and this makes Shin sad. Seeing this, Chae Gyeong comforts him. Shin prepares a car just for her. Hyo Rin manages to persuade Chae Gyeong and Yul to join the equestrian club. Shin's friends are dissatisfied with the whole idea of inviting Chae Gyeong into the club. Meanwhile, Shin goes to Thailand in place of the King, who could not go because of his failing health...

Chae Gyeong totals the car that was given to her and gets in trouble. After overhearing some girls at school badmouthing her, she feels hurt and asks Yul to just take her away from the Palace, to some place far away. In, Gyeong, Hwan and Hyo Rin all go to Thailand. Hyo Rin meets up with Shin and asks him to escort her to the airport, and the two end up spending the day together. Meanwhile, the Palace is in an uproar because Chae Gyeong has disappeared.

Chae Gyeong is confined to the Palace as punishment for leaving the premises without permission. After seeing Chae Gyeong in trouble, Yul asks Hwa Yeong to make him the Crown Prince. With the help of Yul, Chae Gyeong successfully finishes the welcoming ceremony for Prince William. Hwa Yeong starts to reclaim her and her son's rights by seeking favor with the King. Chae Gyeong, who has been waiting for Shin to return from Thailand, finally meets back up with him.