I liked how the drama started, the concept wasn't something unseen but it had his elements of uniqueness.
That element were the kids and the neighborhood. I especially liked how the clueless parents actually discovered key informations without even knowing, it was refreshing and I felt good because usually in spies movies and shows the organization members are too superior to commoners (must be that way to protect the country right? Still, to me flawless people are annoying) and the whole babysitting was cute to the max (those two kids are so pretty and sweet! And I don't even like kids lol).
Also Go Ae Rin was a good female lead, some of her decisions and justifications were not the best (you won't poke your nose around to a dangerous place like j int. out of mere curiosity, they could've make her connect her husband death to that place in order to give her a solid motive to investigate. Like not the whole plot, it would be marysueish xD just an hint...) she still was a complete character with a growth through the drama. I liked her courage.
I think tho, the husband was forgot pretty fast...even if that character is just a catalyst for her to be introduced into the spies world, he was her loved one, the man who was the father of her chilchildren...they tried to justify with "I have to stay strong for my children" but still it felt weak to me.
The spy plot...let's say I like all the reference to all the famous spy movies like mib, 007, kingsman, uncle, and so on. As I said I really find exciting to see how this world collided with the commoners world, but this faded away, especially towards the end. I guessed who the evil ones where and their motivation/plan was really predictable. I admit I skipped towards the end.
The romance was meh..., they started too fast but more consistently and then they backed up in the middle. There are no kisses, just that nose-nose thing with the child and occasionally with the male neighbor who's lowkey gay for the main lead. (There is an hint of bromance between them and the two male leads)
Another interesting character was Young Tae, the conman/thief that's not really the worst person in the drama. I saw this actor in Go Back Couple and I really liked him, he's not as handsome as Terius (truthfully I am not in for the looks, but I fall hard for charisma xD) but he was more interesting to me. So Ji Sub is not a bad actor, but he has always that stoic emotionless scheme in every drama I watched with him (maybe I just picked the ones that are similar), I admit it was a good contrast with the children but the second male stole some spotlight!
The worst thing probably was the product placement. I can forgive the plot holes since I watched it as comedy (so I did't pay too much attention to the evil people plot xD), but the advertisement was a little over the top. Too many products and too much footage of them sponsorizing coffees, fast foods, beverage, jewelry and so on. It was too obvious and ruined the mood :(
It was cute but not to the extent of rewatching it in the future.
I don't recommend it if you like mystery and romance, more like if you're into cute comedy and slice of life