College student Nao Kanzaki has always adhered to her name's meaning: foolishly honest. However, after opening an unsolicited package containing one hundred million yen, she inadvertently accepts an invitation for the Liar Game. In this tournament, contestants are encouraged to betray and deceive their opponents to gain a massive amount of cash; conversely, losing will incur a lifetime debt. With all hopes lost, her only option left is to seek help from a con artist. On that same day, the infamous swindler Shinichi Akiyama is finally released from jail. This former psychology student is known for single-handedly bankrupting an entire company, and Nao believes he is her only chance at escaping her dire situation. At first, Shinichi is hesitant to commit another crime, ignoring Nao and her request. But after seeing her desperation and persistence, he agrees to assist her. In this fraudulent world, Nao and Shinichi have their own motives. Yet, soon they see the true nature of not only the game, but also everyone involved.

An abnormal phenomenon has been observed in Kaga, where Akina and his friends live. A town shrouded in thick fog, a great tower standing sentinel… This is the Fantasma. ——On the night when the crimson moon rises, they shall become Fantôme. (Source: Official Site)

After inheriting the company from their parents, siblings Yuuhi and Yuamu Oudou have started to work at the Alien Trouble Consultancy, an organization that hunts aliens. Although they have never encountered aliens before, Yuuhi is desperate to meet one as he believes that an alien has stolen his important item, called the Earthdama. One day, while searching for extraterrestrial creatures, Yuuhi and Yuamu find a strange spot in the forest where many trees have fallen, forming a scenery similar to a crop circle. As they venture further, they discover a mysterious spaceship and enter it out of curiosity. To their surprise, they come across Yuudias Velgear, an alien from the Velgear Star Cluster. As it turns out, Yuudias is seeking to learn about Rush Duel—a card game popular among elementary school students—as he believes that it will save his home from a long war. With the siblings agreeing to teach Yuudias about Rush Duel, they eventually realize that their first contact with an alien may not be a random coincidence.

Ninth season of Cardfight!! Vanguard: D Series.