I always have a feeling that this manga is wearing a mask. It's a slice of life harem manga that doesn't feel like a harem manga, but definitely is one. Let me explain:
The story is about a highschooler named Daisuke that gets roped into the "Mystery Research Club" that looks into magic, the occult and hypnotism (one for each of the main girls). Within the club, they get into random situations that usually consist of the girls experimenting with Daisuke or testing out one of their individual "mysteries". It's all pretty lighthearted and funny, and the situations they find themselves in are usually more interesting than the average slice of life school comedies that are so common.
As the story progresses, more and more girls get added into the antics which is why this is a harem manga, but nothing really romantic comes out of anything. There are a few chapters where it's obvious that some of the characters are into Daisuke, but it plays more into comedy than manga which is why it doesn't occur to me that this is just harem. It's more just like a group of friends having fun, that just so happens to consist of one guy and a bunch of girls.
That all being said, the characters are pretty likable, though they do fall into their respective stereotypes. The way they break the mold is in their particular interests, which makes them a bit more interesting.
The art style is simple, but clean and fits the tone of the story pretty well.
Overall, I really enjoy this for some reason. It's a fun ride with each of the individual main characters as well as the occasional side ones. I can't explain the appeal of this very well, but check out the first few chapters to get an idea of the rest
tl:dr- seemingly average harem slice of life high school comedy that is somehow a lot more interesting than it appears to be
