In episode 11 of Dance in the Vampire Bund, “Underworld” (アンダーワールド), the hunt for Akira has spilled over to public areas where the “general public” mills about, except this is a rather special group of the “general public”: This is the Bund, so they are all vampires. Becoming a vampire definitely seems to addle people’s brains a bit, since when confronted by a homicidal maniac who is killing everyone in her path during her hunt for a single person, they all go berserk and start attacking her to no avail.
Akira only gets a reprieve when Alphonse, the one in charge of the “we don’t do that sort of stuff” division, shows up in his car to extract him. Akira insists that Alphonse talk about what’s going on, and he gets an answer: the surviving three royal families basically were usurpers who killed off all the other pure bloods and even the previous vampire queen Lucretia, Mina’s mother, while Mina was only left alive supposedly because killing her would leave no pure blood female behind to continue the species. In reality, it’s more so that the perverts can humiliate Mina Tepes every ten years or so for the “sake of checking up on her suitability as a mate”.
Akira decides to jump back into the fray while asking that Alphonse pass a message on to Mina that he will survive and that she should fight as well. When Mina gets the message, she remembers the first time she lay eyes on Akira seventeen years ago, which was right after a humiliating session with the perverts after which Akira’s innocence cheered her up. The renewed determination prompts Mina to join the outstanding bet among the perverts: she will put everything on the line, betting that Akira will emerge victorious, and she will win her freedom if she wins.
Among the “everything” that Mina bets, one of the perverts is particularly interested in a specific item, but Mina isn’t sure what he’s talking about. It seems to be related to whatever Akira had seen in Mina’s castle right before he lost his memories during a secret mission a year ago, though. After a heavily armed Mei Ren showed up to save Akira from another assassin (where it turns out that she is among the last of a dead family and also a werewolf (and not the vampire she originally implied herself to be), and her romantic overtures were rebuffed by Akira, who has stronger feelings for Mina), the main assassin in this episode shows up again, and this time she is much more interested in trying to get Akira to reveal what he saw a year earlier.
Having been separated from Mei Ren and being unable to transform into a werewolf for what are presumably psychological reasons, Akira can’t do much while the assassin beats him up and psychologically torments him by transforming into Yuki, all the while demanding that he reveal what he saw. She was making good progress in the mind games department until she took Mina’s form, and that was a big mistake. This breaks Akira’s psychological block, and in a rage, he bites off the assassins head for daring to impersonating Mina Tepes.
Akira probably has regained his memory of whatever terrible secret that he learned during his secret mission of a year ago, and the implications for his relationship with Mina might not be pretty, considering how everyone in the know seems to think he’ll end up an enemy once he remembers. I could be wrong, though: it seems I’ve been wrong about Mei Ren as well. Whatever the case, I don’t think Mina or Yuki have any idea about what is about to transpire, even as they worry about what is happening with Akira.