the link between case + time
Well, just found out the serial murders featured in Tunnel is based on a real-life case that also inspired Gap Dong. Thus, the parallel between the two dramas. Our resident hard-headed, brash detective from 1986 is teleported to 2017 where he meets a cool, calculating detective and a chilly profiler, who declares she is mad about psychos. When similar cases start popping up in the present, our vintage detective concludes that if he can solve the case here and now, he can return to the past. It does sound plausible enough and I already find the trio of characters individually interesting.