After publicly announcing the terms of the Gate Battle, Howard takes Rio and the others on vacation to an island town to relax before the battle. While looking for Rio, Mint meets an old man, who explains Rio used to come to this place with Rina and Risa when she was young. Meanwhile, Rio visits her old vacation home where she almost discovers Rina before learning that Mint had gotten lost trying to find her. Mint is found by Rina, who uses her Roll Ruler to protect her from a bear. As Rina returns Mint to Howard, he tries to explain that Cartia is lying to her, though she says that even if it was a lie, it has made her stronger. On the night of the Gate Battle, which is to be a 15-game match of poker, Joker takes Elvis' place as the dealer. Rina wins the first two games using her Roll Ruler, but Rio hints she has a trick up her sleeve.
リオ対リナ――世紀のゲートバトルまで、あとわずかに迫ったある日。ハワードの提案で、リオたちは海岸沿いの美しいリゾート地へと出かけることになる。温泉に卓球と、思う存分リゾートを満喫する一同だったが、リオはひとり、街外れにある別荘へと向かっていた。そこはかつて、リオがリナや母親のリサと過ごした、思い出の場所だった。脳裏に蘇る、楽しかったあの頃。そんな彼女を、意外な人物がじっと見つめていた……。
