Sentinel AU with a twist: In the world, some people are born with strange powers. Often, people with powers go about their life not realizing the true extent of their abilities, merely using their powers for a parlor trick or as a convenience.

Recent research, however, has shown that these abilities can be grown to be much more powerful. From a new branch in government, these people are sponsored to grow stronger. To do this, they must become Bound.

The Bound are partners that can cultivate their full potential by being ‘bound’ together. Being Bound means more than working closely together. It means becoming nearly one entity from two bodies. To heal, they require intimate skin contact. To stop from overloading, they must become emotionally in tune with each other. It is hard to find a perfect match, which is why there are so few Bound parters.

Minseok is Bound with Junmyeon, who is in a coma from a past incident. He wants to retire, but the Director of the Specialized Branch has other plans for Minseok.

A new generation of young people with powers has entered the training facility in Seoul. The new trainees are paired up quite easily. All except for one...