Uploader The time machine which was invented in 2021. The phase shift through the quantum transmission of polymeric compounds introduced by Han Tae Sul at the ŌĆśQuantum & TimeŌĆÖ conference is the foundation to the ŌĆśuploader.ŌĆÖ To explain how the uploader works, it is like a fax that scans the information of objects in a place and sends them to another. As a time-loop is possible, Kang Seo Hae (Park Shin Hye) has repeatedly crossed over to the present in an uploader to prevent Han Tae Sul from developing an uploader at all, and so protect the world. Such is written in the diary she brought with her. Downloader If an uploader sends you from the future to the present, the device that receives what is sent from the future from the present is a ŌĆśdownloader.ŌĆÖ Its probability of succeeding is extremely low as it is still at an unstable stage. Errors often occur on the way as people go through abnormal changes or die. This is why the sniper at the Busan conference who aimed at Tae Sul had an odd appearance. Smugglers Those who come from the future to the present are called ŌĆśsmugglers.ŌĆÖ Kang Seo Hae, Han Tae San, Asia MartŌĆÖs boss Park, and his employees all live in hiding as they have not been invited. These people all come in fairly simple clothing when they cross over, and this is to reduce the possibility of an error of the downloader by minimizing information values. If they share a common feature, itŌĆÖs that they all bring a black suitcase. In it contains each of their items which helps them achieve the purpose of returning to the present. The Bureau of Enforcement The reason why smugglers have to be on the run as soon as they arrive is because of Section 7 of the Foreigner department from the Immigration Office. Also called ŌĆśBureau of Enforcement,ŌĆÖ they control illegal smugglers. As society became chaotic due to an increased amount of people who jumps from the future to the present, they arrest and handle illegal smugglers in order to maintain public order. Even those who have contacted the illegal smugglers are under their radar. Once caught by the Bureau of Enforcement, itŌĆÖs hard for one to return home alive. Broker Whilst there are people chasing after smugglers, there are others who help them. This is Asia MartŌĆÖs boss Park, who calls himself an ŌĆśunofficial embassy.ŌĆÖ He is a sort of a ŌĆśbrokerŌĆÖ who helps smugglers come through without a connection to settle down in the area by keeping them out of the Bureau of Enforcement. Of course, nothing is free in the world. He calculates and makes sure to get his interests upon interests upon interests, and even claims that the items brought by the smugglers belong to him. ┬Ā Source (1, 2)