When your fate is to save another world, how are you supposed to react?

Amelia Jung is a 20-year-old Korean girl on planet earth, on her 21st birthday she finds out that her 'parents' are actually her paternal uncle and aunt and her fate is to be sent back to 'Exo planet' which is where she is really from, to save the planet from destruction and in the process find out her true identity which has been kept hidden for all these years.

Upon being sent there, she is met by a man by the name of Kim Jongdae, commonly known as 'Chen' who in turn helps her by letting her stay with him and the rest of Exo.

Once she meets them, however, she realizes that one of the twelve members is the key to finding out who she really is, why she is so important and how Exo come into play.