In their new adventure, Yuuna and Stitch move from their small island Izayoi to the Okinawa main island where Yuuna is supposed to visit a school. A new cast of friends awaits them there as well as a new crisis approaching from space. (Source: AniDB)

In the Victorian era, the British Empire is bustling with the energy of the steam-powered industrial revolution. Following in the footsteps of his famous family of inventors, James Ray Steam enjoys his youth in Manchester helping at local factories and stealing components for his own creations. One day, he receives a package containing a strange ball with an attached valve from his grandfather, who has been working in the United States alongside Ray's father. However, it is not long before people from the O'Hara Foundation storm into his house demanding he hand it over. Confused and afraid, Ray attempts to flee to the home of his grandfather's colleague, Robert Stephenson, with pursuers hot on his trail. While Ray seeks to piece together the secret of the ball and discover the power it contains, it seems practically everyone in the British Empire is ready to seize it from him.

During Japan's Taisho Era (1912-1926), a scientist named Ayanokoji developed the Steel Angel - an artificial humanoid with superhuman physical abilities. While the Imperial Army wanted to use the Steel Angel as a new means of modern warfare, Ayanokoji wanted his creation to be a new step in the future of mankind. Thus, he defied orders from the Army and secretly made the Steel Angel codenamed Kurumi. Then one day, a young boy named Nakahito Kagura snuck into Ayanokoji's house as a dare by his friends and stumbled upon Kurumi's lifeless body. A sudden attack by the Imperial Army shook the house, causing Kurumi to fall on Nakahito. At that moment, their lips met, and Kurumi woke up from the kiss that started a miracle. (Source: ANN)

The eccentric, self-proclaimed mad scientist Rintarou Okabe has become a shell of his former self. Depressed and traumatized after failing to rescue his friend Makise Kurisu, he has decided to forsake his mad scientist alter ego and live as an ordinary college student. Surrounded by friends who know little of his time travel experiences, Okabe spends his days trying to forget the horrors of his adventures alone. While working as a receptionist at a college technology forum, Okabe meets the short, spunky Maho Hiyajo, who later turns out to be the interpreter at the forum's presentation, conducted by Professor Alexis Leskinen. In front of a stunned crowd, Alexis and Maho unveil Amadeus—a revolutionary AI capable of storing a person's memories and creating a perfect simulation of that person complete with their personality and quirks. Meeting with Maho and Alexis after the presentation, Okabe learns that the two were Kurisu's colleagues in university, and that they have simulated her in Amadeus. Hired by Alexis to research the simulation's behavior, Okabe is given the chance to interact with the shadow of a long-lost dear friend. Dangerously tangled in the past, Okabe must face the harsh reality and carefully maneuver around the disastrous consequences that come with disturbing the natural flow of time.