고 돌아가다

head back doing something

The -고 clause says how or with what you go back: 임무를 마치고 돌아가야지 "I should head back once the mission's done", 4호선을 타고 돌아가잖아요 "you take line 4 back". 타임머신을 타고 돌아가다 "go back in a time machine" turns up twice as the way to talk about revisiting the past. Watch for 돌아가신 분 in one line — with the honorific -시, the same verb means "passed away", not "went back".