Finally, Tunnel offers a South Korean time-warp crime drama worthy of comparison to Signal, the 2016 sensation.

Tunnel, in which a dedicated police officer, Park Kwang Ho (Choi Jin Hyuk), chases a serial killer through a tunnel in 1986 and is mysteriously transported to 2016, isn't as nifty a detective story as Signal.

Its set-up - the time traveller assumes the identity of a young policeman and works with new colleagues, including his aloof, efficient partner, Kim Sun Jae (Yoon Hyun Min) and their icy criminal psychology consultant, Shin Jae Yi (Lee You Young), who may be better equipped to stop serial murderers - even seems run-of-the-mill.

Four episodes in, however, the penny drops and I realise Tunnel is a quirky, riveting relationship drama.

Kwang Ho has a poignant reunion with his subordinate, Sung Shik, who used to worship him and who can't believe that he is alive, after disappearing for 30 years. Awkwardly - but also amusingly - Sung Shik is now Kwang Ho's superior and they have to sneak around at work. Their colleagues are detectives, after all, and they might suspect something if they overhear the boss being warm and deferential towards the new boy.

Sun Jae and Jae Yi begin an offbeat mating dance, making curt phone calls during investigations, hanging up and keeping each other guessing.

Kwang Ho has lost three decades overnight and, some days, he is more anxious to find his wife, who has moved out of their old neighbourhood, than to crack the case that brought him to the present.

Tunnel is less dynamic than Signal, in which investigations across time overlap, diverge and merge. Over 16 episodes, the central characters are revealed to be more closely related than they think and their backstories fit together like jigsaw pieces.

Nonetheless, amid the machinations, Tunnel locates the human element, the wellspring of emotional truth. Many of the characters have lost someone, and the drama grasps just how intangible loss is.

A daughter who has never really known her parents, for example, cannot begin to comprehend what she has lost. Instead, she lives in the shadow of a vague sorrow she can't shake off, longing for something (love, security, or a memory of having been loved?) she can't quite pinpoint.

With The Lead, Channel 8 is stepping back in time, but maybe also following in the footsteps of Reply 1988, the 2015 Korean nostalgia drama.

Much of it plays like a mash-up of Mediacorp's navel-gazing Dream Makers series, which is set in and around a Mediacorp-like studio, and Reply 1988, which has a retro village feel.

The decades-spanning tale of four friends (Rebecca Lim, Shaun Chen, Andie Chen and Julie Tan), their families and their careers in a national broadcasting company is pleasant, and a few performances are pleasurable.

Chen Hanwei plays Lim's dad, a Hong Kong-born stuntman who was among the pioneers of home-grown television. He sports Jackie Chan's haircut and a heavy Cantonese accent. It's a one-trick performance, but a great trick.

Andie Chen is kind of wonderful as the jerk next door.

Resentment follows him like the smell of cheap cologne, and yet his character, an insecure wannabe actor with foot-in-mouth disease, is completely relatable and strangely likeable.