"Trigger" doesn't quite hit the mark.
This series feels like a string of encapsulated morality tales, espousing the dangers of unfettered access, to firearms. Any pro gun control advocate, will, I'm sure, applaud it. Others might point out that Switzerland has high levels of gun ownership but low levels, of gun related crime. In any case, when viewed through the lens of entertainment, this series quickly becomes repetitive and tiresome.
It's like an elaborate, drawn out version of one of those crude, cautionary safety video's, they torment kids with, at school. "Don't play with matches, "Guns are dangerous", you get the idea.
Acting, as is so often the case with South Korean drama's, is well above average. There are interesting characterisations on offer too but they are constrained, by the limitations in the script.
In summary, a little too repetitive, simplistic and preachy for my liking. A broader story, with a subtler message about gun control, might have worked better. A mediocre watch.