A deadly virus known as "Algernon" has attacked humanity with vicious meaning. At the forefront of the battle is the mystifying Akamatsu Industries—disguised as a heavy machine factory in Tokyo, this undercover organization uses neural enhanced weapons known as NeuroNoids to battle Algernon. Also helping with their secret efforts is the mysterious mutant who is only known as "Betterman." (Source: ANN)

Many years ago, the death of the emperor sparked riots and civil wars that ravaged Atlantia. Upon the throning of the young king Yaiba, treacherous rebels were executed to restore the peace the country once had. However, tainted by this radical act of governance, Atlantia continues to be enveloped under the shadow of oppressive rule. Tsurugi Tatewaki is a spunky teenager who grew up in the rural countryside with little memory of his birth parents. One day in his home, he stumbles upon a mysterious sword that transforms into a Battle Spirits card. When armed forces from Atlantia confront Tsurugi with their sights set on procuring his card, the secrets behind Tsurugi's past seemingly begin to unravel. Accompanied by a droid named Bringer, Tsurugi makes his way to the capital of Atlantia and encounters supposed warriors who wield similar swords. As his world is slowly turned upside down by the gradual appearance of greater mysteries, Tsurugi may have to question everything he knows, including his very own judgment on what separates good from evil. [Written by MAL Rewrite]

The film is about 4 high-schoolers who are bike racers and illegally partake in races at night on public roads.

Primary school student Keita Amano's curiosity is as innocent as any other child's his age. But when one day he decides to venture deeper into the forest, he encounters a small and mysterious capsule. Out from its depths comes Whisper. After 190 years of imprisonment, this ghost-like creature is glad that someone has been kind enough to set him free. He decides to reward Keita by becoming his guardian against supernatural forces. Whisper is one of many Youkai that exist in the world, and provides Keita with a special Youkai Watch, which enables him to see and interact with all the other Youkai. Youkai Watch follows Keita, Whisper and the cat spirit Jibanyan as they encounter Youkai, befriend them, fix all the trouble that they so often cause, and, with the help of the watch, use the powers of previously encountered Youkai to aid them. Young Keita may have been just an ordinary primary school student when he first encountered the Youkai, but the many adventures that follow his discovery provide him with invaluable experiences and precious life lessons that help him grow.