Rio: Rainbow Gate!

Mint Clark goes on holiday with her grandfather to the Howard Resort. While her grandfather enjoys the casino, Mint explores the resort and eventually meets the casino's most famous dealer, Rio Rollins Tachibana. As Rio and Mint go for a walk, they are approached by a man and his henchmen who attempt to take Mint's teddy bear, Choco, but Rio fights them off. After Mint bears witness to the good fortune that Rio brings to her customers in the casino, they are once again approached by the man, Orlin Dunhill, who decides to play a game of closed poker against Rio for Mint's bear. Orlin makes a gamble to get four Queens though, but thanks to Rio's ability to communicate with her cards, he loses out to Rio who wins with a pair of twos. Afterward, Orlin explains he had been collecting rare stuffed animals to fulfill his sorrow from being dumped at the altar, only to then find that Mint's bear isn't a Belgium original.

Rio is asked to train a new recruit named Anya Helsing to be a dealer. Anya is quick to point out that Rio owns a "Gate", one of thirteen rare cards that are wagered in battles with other "Gate Holders" to determine the strongest dealer in the world. Although her dealer skills are quite good, she is rather clumsy, causing some chaos in the casino. Meanwhile, a Gate Holder named Elvis comes to challenge Rio to a Gate Battle set on a giant roulette table. Although Elvis has confidence is his prediction of numbers, he ultimately loses to Rio when a bandage he was wearing on his finger comes off while throwing the ball, allowing Rio to guess correctly and win his gate.

Howard takes Rio to a supposedly haunted castle which used to feature a casino owned by a woman named Misery, with plans to refurbish it as part of the Howard Resort. During the stormy night, lightning strikes the castle, which frees the ghost of Misery, who goes to the Howard Casino and spreads bad luck. She attempts to try and win the casino in a game with Anya, but instead falls victim to her clumsiness and freaks out. Misery later attacks a chicken wing delivery van, and when employees El and Il Adams discover her, they are attacked too. The next night, Rio gets a call from fellow employee Rosa Canyon, who had been possessed by Misery's spirit. Upon returning to the castle, Rio finds Misery, who challenges her to a game for the Howard Resort, having already taken control of El and Il and kidnapped Howard. The game involves betting to see if the dice will land on an odd or even number, but Rio is troubled by Misery's illusions. However, they are dispelled when Misery eats a super-spicy chicken wing she got from a mysterious delivery girl, allowing Rio to win the game and free Rosa. As Rio chases after the delivery girl, she reveals herself as her childhood friend, Rina, who has also been recruited by Howard.

Rio takes Rina on a tour of the resort, introducing to the other employees. Rina also notes that Rio is a Gate Holder, mentioning how Rio's mother, Risa Rollins, once owned all 13 Gates. Their date is cut short when a man named Bull Hard takes Anya hostage. He challenges Rio to a vending machine lottery game, but is easily defeated when he tries challenging her to a drinking contest with a hot drink. The next day Rina begins work as a dealer, and her aura seems to make customers weary. Howard then decides to put both Rio and Rina in a game of clay pigeon shooting where players lose items of clothing if they miss; this task made tougher by the wind created by the excited customers. When Rio is at a disadvantage due to the appearance of seagulls during her turn, Rina throws her final turn, ending the match in a draw. Later that night, Howard gets ready for an opportunity with a robotic girl named Linda while Bull is seen talking to a mysterious woman interested in Rio's powers.

Howard sends Rio, Rina and Anya to work at the Sky Resort casino situated at the top of a mountain. Once there, they meet the resort's dealer, Linda, who gives them a tour of the facilities. She is soon revealed to be a robot, and the resort's main terminal. The resort opens the next day, floating itself and its customers high into the sky. Just then, a boy reprograms Linda to challenge Rio to a Gate Battle in which they must both race each other down a giant water slide. The match is a close call throughout, with Linda manipulating the course to catch up; however, Rio wins when Linda loses her head. After the boy relinquishes control of Linda, the mastermind, Cartia Goltschmitt, approaches Howard.

Howard informs Rio, Rina and the others that Cartia had challenged Rio to a Gate Battle against someone named Jack with Howard Resort on the line. Mint asks Linda to draw the culprit who manipulated her data, which leads her to suspect Carlos Tanaka, an Afro samurai with terrible luck, as the culprit. Meanwhile, Rio, who has been getting a lot of silent calls lately, is shocked to find Misery's portrait in her room. As Mint follows Carlos, her bear almost falls off the resort but is rescued by a boy with telekinetic powers who is revealed to be Rio's opponent, Jack Mighty. Jack challenges Rio to a game of Space Pinball for the Gate. Before the match, Mint talks with Jack, who reveals he used to be in a bomb disposal family before he was taken in by Cartia, who just wants to use him for his powers, saying he'll be free if he wins against Rio. During the match, Jack gets the advantage due to his powers but is soon overwhelmed when holographic sharks appear. Rio helps him escape the sharks, but he attacks her ship. However, Rio exits her ship and gets her own back to take the lead and win the match. However, when Carlos accidentally knocks Linda's head off, it activates a more dangerous phase which puts Mint in danger, so Rio and Jack work together to help her and stop the malfunction.