Noel longs to be a Seeker like his heroic grandfather, slaying the beasts that emerge from Abysses and exploring far-off lands. Unfortunately, it turns out he's nothing but a measly Talker–a job with no combat skills whatsoever. Undaunted, Noel sets out to establish the strongest clan in all the land, using his silver-tongued Talker skills to unite assassins and heroes under his leadership.

Hotaru Hinase has lived nearly sixteen years without romance. She is satisfied alone as long as she can enjoy the little things in life with her beloved friends and family. In her mind, she is not meant to fall in love, nor does she understand the concept. While out with a friend, Hotaru witnesses the severe breakup of her schoolmate Hananoi, to whom she has never spoken. Afterward, she sees him sitting in the snow and holds her umbrella over him. To her surprise, this gesture results in him confessing his feelings for her at school the next day. Though Hotaru rejects him, Hananoi insists on letting her get to know him. He does whatever he can to woo her, from changing his hairstyle to finding her lost hairpin in the snow. Although she has no romantic feelings towards him, Hotaru believes that by spending more time with him, she will learn how to love. She agrees to date him and slowly begins to navigate what being a girlfriend entails, including how to reciprocate the kind gestures that Hananoi continues to perform for her.

A plague-like wind blows across the arid, sandy expanse of a post-apocalyptic Japan. As it sweeps over the living and nonliving alike, rust is all that remains in its wake. The cause of the catastrophic state of the world is believed to be mushroom spores. Bisco Akaboshi, known as the "Man-Eating Mushroom," is a wanted criminal archer whose arrows instantly grow mushrooms wherever they land. However, he is in truth a "Mushroom Protector," a person who spreads fungi in order to enrich the land and return it to its previous state. Alongside the crab Akutagawa and young doctor Milo Nekoyanagi, Bisco ventures through the wastelands of Japan searching for the legendary "Sabikui"—a panacean mushroom said to devour all forms of rust.

After discovering that his orphanage was on the brink of closing due to financial stress, Finn, who was living freely on the streets, set out for a casino with the aim of making a fortune. However, nothing could have prepared Finn for the nightmare that was awaiting him. Once there, Finn encountered a car chase and bloody shootout caused by a man's "lucky" card. Finn will eventually learn what the shootout was about. The world order can be controlled by a set of 52 X-Playing cards with the power to bestow different superhuman powers and abilities to the ones that possess them. With these cards, people can access the hidden power of the "buddy" that can be found within themselves. There is a secret group of players called High Card, who have been directly ordered by the king of Fourland to collect the cards that have been scattered throughout the kingdom while moonlighting as employees of the luxury carmaker Pinochle. Scouted to become the group's fifth member, Finn soon joins the players on a dangerous mission to find these cards. "All you need in life are manners, dignity, and the will to bet on your own life." However, Who's Who, the rival car maker obsessed with defeating Pinochle, and the Klondikes, the infamous Mafia family, stand in the way of the gang. A frenzied battle amongst these card-obsessed players, fueled by justice, desire, and revenge, is about to begin! Are you ready? It's Showdown!!