Willy Fog accepts a bet from members of the Reform Club that he can make it around the world in 80 days. His plan, however, does not include being stopped by unknown enemies. (Source: ANN)

Although traumatized by witnessing the murder of his parents by one of the Choushuu, Ichimura Tetsunosuke's thirst for revenge leads him to desire strength. At the age of 15, Tetsunosuke approached the Shinsengumi, wanting to become one of its members. However, Tetsunosuke lacked the skill, mind, and will to emotionlessly cut down whoever threatened peace and the Shinsengumi. Even with the support of his brother Tatsunosuke and his newfound friends of the Shinsengumi, little did Tetsunosuke know the blood and pain he would have to face being part of this historical group.

The year is 2027, and the city of Kyoto has undergone tremendous technological advancement. Within the city lives Naomi Katagaki, a socially awkward and introverted boy with a love for books, and Ruri Ichigyou, a girl with a cold personality who is often blunt with people, but shares his love for reading. Despite having similar interests, Naomi is afraid to approach Ruri due to her unfriendly nature. One day, as Naomi goes out for a walk, a crimson aurora pierces through the sky for a brief moment before vanishing. Shortly after, he sees a three-legged crow and a mysterious hooded man who reveals himself to be Naomi from 10 years in the future, explaining that he has come to change an imminent tragic event that happens to Ruri shortly after they start dating. Initially taking his words with a grain of salt, present-day Naomi follows his future self's instructions and starts getting closer to Ruri, determined to save her. Hello World focuses on the present Naomi alongside himself from 10 years into the future. With the help of his future self, Naomi begins his preparations to save Ruri. Will he be able to change the future? [Written by MAL Rewrite]

A squadron of robots defends the planet against alien invaders. (Source: AniDB)