Well, it could start with some sort of strange magical or scientific accident that brings Naruto and Moka together in a way that leads to her pregnancy. Maybe there's a mission or an experiment gone wrong that causes this unexpected situation. Then the story could focus on how they deal with the news, and the reactions of their friends and families from their respective worlds.
One potential plot could be that there is a prophecy or a powerful artifact that somehow links Naruto and Moka's fates together. As they are brought together by this, they develop a relationship that results in Moka getting pregnant. The story could then revolve around the two of them trying to understand what this means for their futures. Naruto might have to deal with the fact that he's now going to be a father, and Moka could struggle with how her vampire nature might affect the pregnancy. And of course, there would be all sorts of political and social implications in both of their home worlds.
A practical answer is Chapter 190, because it turns the idea into a concrete scene. The chapter opens with Several people who didn't understand fell silent., adds pressure through And it became even more repugnant to him., and ends on Because he saw the pack of cigarettes pinched between Jiang.
Look to Chapter 167 for the clearest answer. It begins with By the experimental field, Qi Tianyu was quite helpless as he watched Wen..., keeps building through He tried once again to pull back his suitcase, but to no avail, as one end..., and lands on Even when getting into the car, Qi Tianyu was.
The best chapter pointer here is Chapter 178, "The Group's Favorite Belongs to No One but Her!". It opens with Wen Jiaojiao is just too unreasonable, why does she have to single out... and closes on Let's not even mention President Shang's own net worth, but talk about his....
The best chapter pointer here is Chapter 189, "Do You Still Like the Gifts from the Program Team?". It opens with Seeing his painstakingly planted roses trashed like this, even as a fan of... and closes on Just after coming out of the bathroom, he saw the landlord's family all....
A practical answer is Chapter 170, because it turns the idea into a concrete scene. The chapter opens with Watching the two who had long remained silent, the PD shifted his position..., adds pressure through I really want to see the chaotic scene!], and ends on [Didn't the other guests also do.
A practical answer is Chapter 184, because it turns the idea into a concrete scene. The chapter opens with Jiang Li can finish the competition alone???, adds pressure through Director Sun, who had witnessed the whole process: "......" This is..., and ends on Slow down, I'm so scared." "Shang.
If you want the clearest chapter reference, go to Chapter 188. Early on, With a "snap," the pencil Jiang Cheng was using to draw broke on the paper.; later, the chapter leans on He looked up, the cold glint behind his glasses sending shivers down one's....
If you want the clearest chapter reference, go to Chapter 151. Early on, Now it was Zhang Cheng's turn to be confused.; later, the chapter leans on The problem lies with He Yun?. By the close, I will have my assistant pay the bill., and the chapter closes with Was he...
If you want the clearest chapter reference, go to Chapter 191. Early on, This change made Jiang Cheng extremely uncomfortable.; later, the chapter leans on It was as if he had been an outsider from the very beginning..