Fraternal twins Si-yeon and Si-ah couldn't be more different. One never wants to leave her room while the other is a big K-pop star.

A new semester begins, but Si-yeon is already counting down the days to the end. Si-ah shoots a commercial with her not-so-collaborative partner.

To reverse the magical mishap, Si-yeon goes back to visit the tarot card reader with Si-ah -- but bad news awaits them.

On the first day of living each other's lives, Si-ah runs into a group of schoolmates and Si-yeon messes up on stage.

Si-ah's singing ability tops the list of search keywords on the internet, but she's not thrilled about it. She also gets a surprising text message.

Gyo-seok and his gang keep testing Si-ah's patience. Meanwhile, Si-yeon and Hae-seong secretly meet up at the rooftop, but someone is watching them.

Si-yeon makes up her mind to enjoy the remaining days to the fullest. Si-ah makes a big mistake while fooling around in Si-yeon's room.

After finally realizing the truth behind recent events, Si-yeon gets scared and starts looking forward to the tarot master's return.

Hae-seong holds a press conference to answer accusations of plagiarism, but dramatic breaking news grabs everyone's attention.

When Si-yeon goes back to the tarot shop, she is greeted by an unfamiliar woman who explains the necklace to her.

With sincere hearts, Si-yeon and Si-ah try to return things to the way they were -- but it doesn't go quite as they planned.