It's been 10 years since the Great War when the Galad Empire launched their attack on Din Republic. As the only one who survived a bioweapon attack by the Empire, Lily decides to become a spy to protect her country. Unfortunately she is not a quick learner and ends up finding herself transferred to a training academy where other slow learning spies like herself are gathered. There, tasked to train them is the world's "top spy" Klaus but he himself is a bit of a odd person too and isn't very good at teaching.

When Lily and her new Team Lamplight classmates begin to suspect there just going tobe sacrificed, she threatens their teacher to transfer them away. However, obviously she was no match the the world's top spy. Instead she ends up giving her teacher a new way to train his pupils; they must defeat him before they are ready for Mission Impossible. And so our newly formed team of seven continues their training and builds up the bonds that keeps them together. 

I haven't read the original light novels but from what I've seen this is supposed to be a poor adaptation of it.

It feels like a really familiar setup from the get go just that you throw in a variety of girls in with your archetype personalities. I almost stopped watching some way through the first episode but the little surprise compelled me to keep going.

The direction's kind of odd. A quick tease of the future before flashing back to the past is nothing new but here, it makes you think the whole plot's about training the girls before they go on their big mission then suddenly it's already done 3 episodes in. Then it's just back to this everyday life of spy training.

I say everyday life but you can think of it as one of those comedy slice-of-life shows only for spies so, I think they wanted to get the only serious part of the story out the way.

Funnily there's no OP or ED theme song and music goes with the same kind of composition as Spy x Family. With harem shows there's also some fan service in the form of shower scenes but they're actually quite rare and Klaus actually ends up part of it too.

You can think of it like a harem version of Assasination Classroom only the goal is shown right off at the start so the rest of the show feels completely pointless, like watching the slice-of-life of assassins in training failing to knock out their teacher.

The lack of variation in personalities just makes the rest of the show very dull to watch as it becomes a strange slice-of-life show. Just a bunch of girls coming up with an elaborate scheme to defeat their teacher only to fail but in a boring way compared to our octopus Koro-sensei.