But maybe Sera actually comes into contact with the BO. Like, let's say she's investigating the mysterious vanishing of her older brother. She might have seen the news report about the pickup truck blowing up, and put two and two together. She probably thinks her brother is dead and does more research to eventually track down Conan and the gang. Now she's delved a tad bit too deep for comfort. Now let's say the BO pops up once again and Okiya Subaru, scar Akai, Bourbon, Anokata, and the FBI are all brought forth in another epic BO arc. But if you throw Sera in there and get her all tangled up in the mess, there could be some serious advancements in the plot. Even though Eisuke didn't do anything to advance the plot, he wasn't a very described or centered person. He didn't have any skills of any kind except the ability to be careless at the most crucial of times. But Sera is a different story. With her jeet kune do skills and her impressive deduction skills, she will probably do a lot to advance the story plot. That's just my theory.