Naturally, Yoshitaka was inviting Charlie and Claire to the main table mainly because he didn't want Kathleen to think he was mistreating her friends when she arrived later.

After all, Charlie and Claire were important enough that Kathleen had immediately changed her mind about not coming to this party. As such, when she arrived and saw them being sat at some fringe corner, she might have some choice words for Yoshitaka.

For Charlie's part, he definitely understood Yoshitaka's reasoning.

He