Us Back Then, Us Now

The participants are back on Jeju Island and meet again. Lee Hye-seon, Jeong Hye-im, and Kwak Min-jae from EXchange explore the Jeju sea in a submarine. Park Na-eon, Lee Ji-yeon, and Jeong Gyu-min from EXchange 2 go off-roading to a place where Gyu-min had his EX-date. Kim Kwang-tae and Cho Hwi-hyun from Exchange 3 are glad to see each other. After spending a special time, they gather at the Jeju Island house and meet each other for the first time. What kind of beginning awaits them there?