R-15 is about a boy, Taketo Akutagawa, who attends a school for geniuses: Inspiration Academy Private High School. Taketo is a genius novelist and writes erotica. Despite negative perceptions many people have of him, he aims to be at the top of his class and be recognized as the world's greatest writer.

The year is 20XX. Mysterious huge robots called "Giant Robo (GR)" started to appear all over the world and destroy cities. The earth was covered with fear. And their next target is Japan! The hero of this animation Daisaku Kusama, who works in a diving shop, encounters a mysterious girl, simply called V who leads him to make a contract with an enormous robot "Giant Robo 1 (GR1)" at the ancient ruins (Minami Yonaguni Island) in Okinawa. He made a contract with UNISOM (good guys) and was approved to be a commander of GR1. Thus his battle has begun against GRO (bad guys) and creates a lot of dramas. Before long, Giant Robo of the 21st century will ask the world the true meaning of its power.

After saving the Kingdom of Liones from the 10 Commandments, Meliodas and the Seven Deadly Sins are enjoying their time off. However, things aren't as peaceful as they seem, as the Sins are put through various trials to become strong enough to defeat the 10 Commandments and to overcome their past trauma. With help from past figures, the Sins are tasked with defeating the 10 Commandments and putting an end to their evil plans that began ten thousand years ago. The Sins begin to uncover the truth about each other, as well as those who stood before them. With this knowledge in hand, the battle against the 10 Commandments has only just begun. Nanatsu no Taizai: Kamigami no Gekirin continues to follow the Seven Deadly Sins and those that they meet on their journey. Through their adventures, they realize that their actions have had greater consequences on the present than they could have ever expected. [Written by MAL Rewrite]

Dr.Haneda was developing experimental giant robot warriors to fight the allies during the Second World War, but before his creations could see action, Allied bombs destroyed the facility and killed him. A decade later criminals discovered two of the surviving prototypes, #26 and 27 in the series, and used the remote controlled robots to commit a number of crimes. Young Shotaro Haneda, the twelve year old son of Dr.Haneda, did some investigating and discovered that the mob were hunting for the twenty-eighth robot in the series, rumoured to be the most powerful of them all. Racing the villains, Shotaro discovers the robot first, along with Dr.Shikashima, a colleague of his father's who was also believed killed by the Allied bombing. Together the two prevent Tetusjin-28 (the robot's official designation) from falling into the hands of the bad guys, and decide to dedicate him to peace rather than war. Shotaro fought crime for a long time, supported by Dr.Shikashima, who would repair Tetsujin-28 when he was damaged, and by police officer Otsuka. Shotaro even battled the alien Magmans, invaders from the planet Magma, who came to Earth late in his career, bringing their own giant robots, Magma X and Gold Wolf, with them. (Source: AniDB)