Few Korean dramas get better as they go along. Live shoots, script changes, and attempts to milk ratings tend to sabotage the second halves of shows. It is therefore remarkable that Mixed-Up Investigative Agency actually improves with every episode. It starts out low rent and silly, with broad acting and chintzy production values, but around the halfway mark, it morphs into a moving, tightly written meditation on friendship, life choices, and the way that the past always literally or figuratively haunts the present. Characters who initially seem like caricatures become multidimensional and unpredictable, with especially lovely turns by Ye Ji Won as a crackpot psychic, Park Hee Soon as an enigmatic gangster, and Ryu Seung Soo as an apathetic manhwa vender. Off-kilter visuals, clever dialogue and ingenious music choices provide plenty of humor (don't miss the little bonus scenes tacked on at the end of each episode), but they’re in the service of serious themes. Without ever becoming overly didactic, the show notes the fragility of life and the importance of embracing the here and now. The protagonists may long for extraordinary riches (in this case, tons of hidden gold), but their everyday interactions are where true value lies. For the viewer, though, the biggest prize is getting to savor this underrated gem of a show. Like all treasures, it may be hard to find, but you’ll be well rewarded if you seek it out.