Ten-year-old Sakura Kinomoto is an ordinary fourth-grade student living in Tomoeda until, one day, she stumbles upon a mysterious book of cards titled The Clow. Pondering over her discovery, she unintentionally causes a magical gust of wind to scatter the cards all over town. The accident awakens the Beast of the Seal—Keroberos, nicknamed Kero—who tells Sakura that she has released the mystical Clow Cards created by the sorcerer Clow Reed. Due to each Card's ability to act independently and their incredible power, Clow had sealed them away. Now that they have been set free, the Cards pose great danger to the world, and it is up to Sakura to put an end to them. Appointing Sakura as the Cardcaptor and granting her the Sealed Key, Kero tasks her with finding and recapturing all the Clow Cards. Alongside her best friend Tomoyo Daidouji, and with Kero's guidance, Sakura must learn to balance her new secret duty with the everyday troubles as she takes flight on her magical adventures as Cardcaptor Sakura.

For this year's Nadeshiko Festival, Sakura Kinomoto's elementary school class is presenting a play. She will portray a princess who struggles to respond to the love confession of the neighboring country's prince. Sakura empathizes with her character all too well, since she herself still owes an answer to the boy who confessed his love for her four months ago. When cousins Shaoran and Meiling Li return from Hong Kong to pay a surprise visit to their friends in Japan, Sakura receives further encouragement to finally declare her feelings. However, she is repeatedly distracted by a presence reminiscent of a Clow Card as well as unexplained disappearances around town. Eventually, Sakura learns of another of Clow Reed's creations—the Nothing—which was formerly sealed away beneath the magician's old house. It has power equal to all 52 cards Sakura possesses, and furthermore, it wants to take those cards away from her! Objects, space, and people disappear from Tomoeda with each card that is stolen. Sakura sets out to capture the Nothing so everything will return to normal, but what must she sacrifice in the process?

Fourth season of Cardfight!! Vanguard G series.

After the sudden departure of a valuable friend, the future of Team Blackout is now uncertain. Yu-yu Kondou and Megumi Ookura feel frustrated for failing to prevent the inevitable, while the heavily involved Touya Ebata is trying his best to atone for past mistakes that led to this misfortune. But whatever they decide to do next, the members of Team Blackout know that they will always find their way back together through their precious card game, Cardfight Vanguard.