The 5th episode of Nisemonogatari takes the viewer on more of a plot driven story than any previous episode before. It begins with a conversation with Tsukihi which seems to go nowhere before the viewer is presented with a reenactment of Karen’s meeting with Kaiki. That’s followed by another conversation with Hanekawa to take her home before Koyomi returns home to take care of Shinobu. After a few minutes, he has an idea to resolve the situation, though he may have to overcome some barriers to do so.
I felt the primary theme that was emphasized throughout this episode was the barrier between childhood and adulthood. Take the opening conversation between Tsukihi and Koyomi as an example.
At the end of the last episode as well as in the first episode, she had complained about Koyomi growing up. The fact of the matter is that by going to him for help and passing on responsibility, she probably felt that Koyomi would become the adult figure in their relationship as siblings. So to keep the connection as children, she successfully gets him to reveal the small number of friends that he had, which satisfied her. Ultimately, she didn’t say what happened to Karen until Hanekawa entered the room. Hanekawa’s relationship with the girls is interesting in itself, but first there was the reenactment.
Earlier, Karen had confronted Kaiki at an undisclosed location for the purpose of inflicting violence on him. The argument that follows goes far beyond just a conman and someone trying to stop them, rather it is a clash between how the world’s economic activity works in reality versus those who see it as unjust.
Kaiki is upfront about his intentions, he wants to make money, and doing so via children who don’t know any better. He also ends up giving an excellent defense for what he is doing. He is accumulating money that can be thrown back into the economy which would make a large number of people happy. In effect, he sees his con activity as a greater good for society. He even presented the best solution for a way out for her if he was paid the profit he hoped to make there.
Karen, still caught in the world of idealism, still believed that stopping his trade in charms was the only answer. That the only answer she saw was violence was incredibly naive. He had leverage the entire time in the form of the bee and he used it well. As soon as she was effected, he was able to demand more money to go away. Then came stealing the money from her wallet which was all about maximizing his return on this trip. She had to be able to return alive so either he got the money he asked for to go away or at the very least warned anyone else about trying to go after him as he collected money from children.
That isn’t to say that Kaiki isn’t evil; he clearly is. It’s his pursuit of money and the willingness to exploit those who don’t know what they are getting into that standout most from this conversation.
Skipping ahead to Karen’s conversation and bed bath with Koyomi, this takes on a different tone from the conversation with Tsukihi. Whereas the earlier one centered around Tsukihi’s need to continue to see Koyomi as a child, Karen wants to be elevated to the level of adult in Koyomi’s mind, though it doesn’t start that way. Stylistically, their interactions are portrayed on a similar level as Koyomi’s to Mayoi when she is embarrassed to be treated so weakly.
That changes as soon as the meeting with Kaiki comes up. It’s immediately obvious that strength has taken on a new meaning for her from the beginning of the day. Money didn’t matter to her before the meeting with Kaiki, now it was very important. She contrasted herself with Kaiki by saying that at least love still matters to her. However, her outlook had become more pragmatic in trying to save the other children caught in Kaiki’s scheme.
Finally, back to Hanekawa, Koyomi and the Fire Sisters. Koyomi is obviously hesitant to allow Hanekawa to have a relationship with his sisters considering her past. However, he knows he’s powerless to stop that from happening and the good points far outweigh the bad ones. She’s intelligent and can help them with all of her knowledge, plus she’s seen as the closest thing to an adult figure they can trust.
So the next episode could potentially be the conclusion to this arc. The use of Shinobu as a replacement for Oshino was fairly predictable from the moment in the last episode when she told Koyomi what was affecting Karen, so it’s not a surprise that her role is more peripheral again. The kiss that Koyomi needs to take on the bee could have all sorts of implications on the relationship he has with his sisters. That will depend how it all plays out.
Lower Mid-Table 
I’d like to believe that this arc, this overall predicament, is a test for Koyomi to see if he can handle things without Oshino around. Thankfully, he didn’t have my reaction after I saw that reenactment, which was to walk the streets until I ran into Kaiki and punch him into a stupor. That would have been very child-like.
As for that potential kiss, as if the scene last episode in the bathtub wasn’t bad enough. I expect a violent reaction, even from a feverish and broken Karen.
That would have seemed like a rational thing to do at the time, hunt Kaiki down and try to kill him. Karen had tried that approach already, so it wouldn’t work. As far as the kiss is concerned, it all depends on how Koyomi explains or doesn’t explain why he has to do that.