The story is exactly as the title says -- main characters are all very smart and you'll love seeing them put their brains at work to survive prison life. There are a lot of characters to keep in mind, but that also keeps every scene interesting without the scriptwriters needing to use stupid tropes/failures to drag the plot out. While there is a lot of life-or-death (and justice) at play, the scenes are also interspersed with amazing comedic relief, keeping the whole show pretty lighthearted and easy to enjoy. The way they use flashbacks as a story-telling device also keeps it interesting and makes it easy for the audience to keep up at the same time.

The casting was so appropriate, and the main characters portrayed the complex emotions so well! Special love to Lieutenant Paeng, whom I had only seen as scary villain characters before (coughcough, I Hear Your Voice). His acting here made me discover a whole other side of him!

Only reason why I didn't give this a higher score is I'm more into heavier/more intense dramas, but if you're looking for a lighthearted human drama with comedic relief, smart characters, and amazing acting, this is a must-watch :)