To avoid the forced closure of the Literary Club's gambling den, the student council treasurer, Aoi Mibuomi (Sano Hayato), orders Mary to face off against a designated opponent. That opponent is Nagi Kamishimo (Atsuhiro Inukai), a top-ranked, formidable gambler at the academy known for reading people and leaving them exposed. Nagi displays an arrogant attitude towards Mary as she takes on the challenge. The game they play is "Full Count Blackjack," a variant of Blackjack using 13 cards, demanding advanced psychological tactics. "I'll break your spirit," Nagi declares, provoking Mary from the start. Losing her composure and falling behind, Mary faces an uphill battle, but the outcome of the match takes an unexpected turn.