Not since last year's Children of Nobody has Korea produced a crime thriller that perfectly combines a great mystery, characters you care about deeply, and a wonderful emotional core that you can connect with every step of the way.

Reeling from the brutal murder of her childhood friend, Cha Young-jin (Kim Seo-hyung) becomes a detective and devotes her life to tracking down the 'Stigmata' serial killer who hasn't killed for 19 years. She is an obsessed workaholic who lives alone but has a somewhat unconventional friendship with her neighbour's young son, the 15-year-old Go Eun-ho (Ahn Ji-ho).

When Eun-ho has a terrible accident, Young-jin pursues the truth with the same determination with which she has approached her friend's murder. And in doing so, she begins to uncover the truth about what happened 20 years ago and why.

Kim Seo-hyung is transcendent in this role as the tough, ass-kicking cop with a heart full of love and empathy. Whip-smart but not cynical, she has the ability to see through people's facades to the core of who they are and provide support, care, empathy and safety to those who need it: a classical warrior fighting to protect rather than to enslave or dominate. It's through this powerful female character that the show examines what it means to be a community of adults to children who need guidance and care.

Young-jin may be grim and black-clad but her home is full of light and plants and is a safe haven for the neglected Eun-ho, forced too young into adulthood. Nobody Knows is full of abandoned, overlooked ducklings needing a mother duck to follow and its overarching question "What happens if the duck that saves them is leading them into darkness rather than the light?" is something it never loses sight of for 16 episodes.

In fact the show's Duckling scenes - children that need to be tended and cared for to grow properly just like the plants on Young-jin's balcony - are Nobody Knows' emotional core and its greatest strength. We care about these children and we want them to be saved. More importantly we care about Young-jin and the way in which the trauma and pain of her life never causes her to lose sight of the kind of person she wants to be.

Young-jin's three most important ducklings - the beautiful ray of sunshine that is Eun-ho, the brooding Ju Dong Myung (Yoon Chan-young) and the privileged but deeply unhappy Ha Min-sung (Yoon Jae Yong) - are a joy to watch as is their homeroom teacher Lee Sun-woo (Ryu Deok-hwan) who gets drawn in trying to protect his young charges.

Are people parasites or symbiotes? Do they prey on each other or build each other up? What kind of adult do you want to be? Is a question asked not just of Sun-woo but of every other adult on the show and of the audience itself.

Not to say that the show is perfect. It isn't. Stretching it to 16 episodes clearly took effort. The show relies too much on a MacGuffin and the back half gets mired in flashbacks and treasure hunts, and even gets a bit heavy-handed. But with an ending that's almost perfect, a beautiful emotional core, and quality direction that pulls you in and keeps you tethered, Nobody Knows is definitely a drama that's worth watching.

It never forgot what it was about and that's a quality reserved for only the very best of Korean television.