Here comes Special Mission, Ssangmun-dong Dads' Challenge! Four Ssangmun-dong dads, Dong Il, Moo Sung, Jae Myung, and Sung Kyun, will take on a challenge for the prizes. Meanwhile, Kim Seol, who played Jin Ju in Reply 1988, the last member of Ssangmun-dong, appears suddenly and surprises everyone.