The Chaser, the sleeper hit on South Korean television in 2012, was about a father's dogged pursuit of the perpetrators of a far-reaching conspiracy to bury the truth about his daughter's death in a hit-and-run.
Now the show's writer, Park Kyung Soo, is back with Punch, a legal corruption thriller that covers similar territory but through a zigzagging path that is more entertaining.
To begin with, the protagonist, Park Jung Hwan (Kim Rae Won), is a ravenous, ambitious prose- cutor whom you cheer on not because you like him, but because he is quick, ruthless and looks most like a winner.
In the power struggle between his boss, the conniving prosecutor general (Jo Jae Hyeon), and their boss, the two-faced justice minster (Choi Myung Gil), Jung Hwan keeps playing dirty and switching sides, but he also seems more consistent than them. You can't accuse him of being a cynic when he admits it himself, as he tells more law-abiding prosecutors, including his ex-wife (Kim Ah Jung): "If the world was like what you think, I would have lived like you."
The show has the heavy score of a melodrama, but the soul of a black comedy. The fun here starts when Jung Hwan goes into a coma during surgery to remove a brain tumour and the boss, after crying over him in hospital and promising a grand funeral, decides to make Jung Hwan's ex a scapegoat for a crime the boss' older brother committed.
Jung Hwan wakes up from the failed operation with only three more months to live, but quickly gets his surgeon to doctor his charts and spread rumours about his miraculous recovery. He knows he won't be able to free the mother of his young daughter from jail if his boss smells blood again.
Circuitously - after enough twists, turns and hairpin bends to almost match a Formula One racetrack - he arrives at a decision to join hands with his ex and bring down his boss. What he wants now is to leave the world a somewhat cleaner place for his daughter, an aim that elevates the show to a guilt-free pleasure.
It sets you free to enjoy all of his dirty tricks, knowing he has just cause for double-crossing the other crooks in suits.
The other two K-dramas of the week, Four Legendary Witches and Healer, follow more well-trodden paths.
In episode one, both shows end with the classic Cupid-at-work moment: boy sees girl, girl accidentally falls into boy's arms. By episode two, at least one protagonist on each show is revealed to be looking for his or her birth parents.
And you see why Hong Kong actor Wayne Lai, defending broadcaster TVB's lack of innovation, has protested that K-dramas have plots out of mouldy Cantonese melodramas too.
The thing is, even a mid-range Korean women's melodrama can be greater than the sum of its plot points. It can tell a story not of things that happen to people, but of the people the things happen to.
Four Legendary Witches, for example, paints with a few deft strokes characters you can care about.
It introduces one of the title characters (Ko Doo Sim), a murder convict who is stiff and slow when she is released for a day near the end of a 30-year prison sentence.
She is being given a taste of what her life will be like when she is freed, but she is bewildered and discouraged when she visits her one friend outside, a retired prison guard, and finds she can't even make the same soup she once made for her family every day. She can't quite put her finger on it, but her soup is weird now. It's different.
She is vaguely upset, until the friend tries to assure her the soup is okay and she has a little meltdown. She has been emptied out by all her time behind bars, she tells him, and she is afraid there is nothing left of her to restart her life.
In a flash, a portrait of the displaced wife and mother she is emerges. You feel for her, and your expectation that she will soon be reunited with her son, a baker, based on the hints sprinkled over the show, is sweet.
Healer is a different show altogether, despite some plot similarities. It is more of a souffle of action and romance: airy, sassy and hardly weighed down by the slice of history the characters share.
Some time in the 1980s, a group of friends ran an illegal, pro-democracy radio station out of a van, but it all ended in tears.
In the present, a private operative (Ji Chang Wook) - a secret agent of sorts who works for a mysterious middle-aged woman - has been assigned a job of spying on an online tabloid reporter (Park Min Young), and he learns they may both be connected to the radio pirates.
It isn't something he and the show worry their pretty little heads about, though.
Rather, the show is more about maintaining a smooth, sexy vibe, as he glides through the night with his parkour moves, watches her from a roof, and insinuates himself into her daily routine as a journalist.
Has stalking ever been more romantic? The show has turned it into an immersive game, and you are all invited to plug and play.