Summer Wars está protagonizada por el joven Kenji Koise, gran amante de las matemáticas y la informática, que tras quedar eliminado a primeras de un concurso de matemáticas a principios de verano se verá con todo el verano por delante y sin nada que hacer. Hasta que la chica más popular del instituto, Natsuki Shinohara, le invitará a pasar las vacaciones a su pueblo con su familia. La razón es que pretende hacer pasar a Kenji por su novio debido a una promesa realizada a su bisabuela. Pero las cosas se complicarán al día después de la llegada de los jóvenes, y tendrán que enfrentarse a una fabulosa aventura en un mundo de fantasía junto al resto de la familia comandados por la abuela.
A young boy named Gusukō lives in the countryside with his parents and little sister. A string of droughts and other natural disasters tear the family apart, and Gusukō is forced to leave home and seek his fortunes on his own. Driven by a desire to improve the quality of life of his poor countrymen, he eventually joins a group of scientists called the Ihatov Volcano Department; he takes part in scientific projects to fight the natural disasters that drove him from his home.
Nicky no es una niña como otra cualquiera porque es aprendiz de bruja. Con solo 13 años y por tradición del oficio que está aprendiendo, la niña tiene que abandonar la casa de sus padres y buscar algún sitio donde sean necesarios sus servicios de bruja. Para emprender el viaje, Nicky se acompaña de su amigo Jiji y también de su gato; juntos, y sobre una escoba voladora, los amigos se instalan en un pueblecito que da al mar, donde la niña empezará a conocerse verdaderamente a sí misma.
In the aftermath of a war fought by magnetic weapons which caused massive earthquakes, a young and spunky boy naned Conan gets involved in a grand adventure. Conan lives in a world that is mostly oceans; the major land masses having been destroyed by the weapons of the great war. He meets a young girl named Lana, and they eventually foil the plans of the city-state of Industria which wants to regain the lethal weapons.
A young Italian boy named Marco is devastated when his mother must leave home to work in Argentina to pay off the family debt. She sends the family letters, but soon the messages stop coming, which worries Marco and sets him off on an epic quest to find her.
In the aftermath of a war fought by magnetic weapons which caused massive earthquakes, a young and spunky boy naned Conan gets involved in a grand adventure. Conan lives in a world that is mostly oceans; the major land masses having been destroyed by the weapons of the great war. He meets a young girl named Lana, and they eventually foil the plans of the city-state of Industria which wants to regain the lethal weapons.