In episode 10, Yumeko and Kira face off in a high-stakes gambling game where the ultimate prize is the antidote to a poison they both ingested. This intense showdown is the climax of the season, with both characters suffering the effects of the poison while competing against each other.

Yumeko is locked in a room by Dori, under Michael's orders, to prevent her from reaching the top of the leaderboard. However, she discovers a secret passage behind a shelf leading to the abandoned Kakegurui Club room. Using a chip given by her mother as a key, she accesses the room and, with Wendy's help, spreads the word to gamble until midnight, successfully continuing her climb.

Episode 10 opens with a flashback to 15 years earlier, showing Yumeko's parents unveiling a new financial invention—a digital currency called Bitcoin—to the Kakegurui club members who had financially backed the project. This scene establishes the deep connection between Yumeko's family and the club's origins.

The chip given by Yumeko's mother serves as a key to the secret Kakegurui Club room, which Yumeko discovers through a hidden passage. This allows her to access the abandoned hall filled with gambling games, enabling her to continue gambling and strategizing to reach the top of the leaderboard.

In the final episode, after sharing a surprising kiss and both being poisoned, Yumeko and Kira's relationship becomes complex as they are forced to compete against each other for the antidote. Despite being opponents in the high-stakes game, their interaction includes moments of alliance and tension, highlighting a multifaceted dynamic.