WHAT'S DANMACHI?

"Dungeon Ni Deai Wo Motomeru No Wa Machigatte Iru Darou Ka? Familia Myth", translated in "Is It Wrong To Try To Pick Up Girls In a Dungeon? Familia Myth", or simply shortened to "DanMachi" (from the pronounciation of Dungeon and "Machigatte"), is a series created by the Japanese author Fujino Omori.
It started as a light novel series in 2013, and recieved an anime adaptation in 2015. As of right now, it counts 4 5 anime seasons, a movie, a spin-off season, 19 LN volumes in the main series, 4 light novel spin-offs, manga adaptations and many videogames.

THE SETTING & THE PLOT

The story takes place in Orario, a city known for its beautiful women, strong adventurers, and the Dungeon.
As we can clearly see from the title, the Dungeon is a fundamental part of the series: it's situated in a tower, commonly called Babel, and it's divided in different floors. Each floor, starting from the top one, has different monsters and the level of difficulty gets harder, the deeper you go. Many adventurers try to explore new floors, but only the strongest ones can reach the bottom!!
In the city of Orario there's not only mortals, but also some gods that descended from the sky to give people their blessing, called Falna. Once a person recieves divine Falna, they become apart of that god's/goddess' Familia.

In this context we see our main character, Bell Cranel, a 14-year-old boy which moved to Orario after the death of his grandfather, the person he lived with. Here, after searching for some hospitality, he gets blessed by the goddess Hestia, a minor goddess (one of the three virgin ones) and goddess of the Hearth.
Bell becomes Hestia's only child, and he starts training in the Dungeon. One day he tries to go down to level 5 - a relatively easy level, but not for a beginner - and he gets chased down by a minotaur that had escaped the lower floors. When he thinks it's all over, he gets saved by a girl: Ais Wallenstein, the Sword Princess, one of the members of the Loki Familia.
Since then, Bell catches feelings for this beautiful yet mysterious girl - feelings that will contribute to his growth, thanks to his skill Liaris Freese that allows him to rank up faster than anyone else.

I find it kinda ironic how the whole situation is flipped: Bell, as his grandpa always said, was supposed to go in the Dungeon to rescue some ladies (bro had to pick up girls in the dungeon, isn't that the title after all??), yet a lady saved him!!
From this moment onwards, Bell will constantly try to become a better adventurer, aspiring to be just like Ais so he can be a hero by her side. Little does he know that being a hero is quite hard, especially when you attract the attention of so many gods and the whole city talks about you...