Mc go to a city near sea with his female member. Mc mission is to find the fault who govern the city. There is dungeon near the city. But you need a local helper to go there. I think the local helper is a race that can breath in water. The female local helper hate the person who govern the city. I dont remember very much, but mc female member working in the bar to make distraction, when mc and the female helper sneaking to some factory. In that factory mc and the female helper see her clan are worked to dead. Mc make some explosion and run to a clif near sea and fall down. The pursuer think mc dead after he fall down to sea. But because he was together with a female helper who know the area. Mc wake to know that he is in the dungeon. The enemy attack the dungeon with a ship. The female helper get hit. To save her, she need to drink something that make her half goddess. The last that i remember is the dungeon is part a city that go upward from the bottom of the sea.