Kim Junmyeon is a thief for hire who retires after nearly being caught by the police and having his true identity revealed. However, he is thrown back into the criminal world when he receives an obscure letter requesting one last heist, titled The EXO Project, and signed with the mysterious initials, CL. Although he knows he should stay in hiding, he abandons his inhibitions and accepts the curious mission. 

Joining forces with eleven of the best hackers, fighters, and technicians in the business, he orchestrates the ultimate team to carry out the mission of stealing over 50 million dollars in precious jewelry and royal samurai swords that have been kept safe in the national museum for centuries. 

As they get closer to completing the job, they find that they being chased not only by the authorities, but also by another group of underground thieves, who seem to be after the same treasure.