Kyoukai Senki Episode 1 English Subbed

In the mid-20th century, due to economic collapse and a shrinking population, Japan became a failed state, necessitating foreign nations to intervene. However, this began a war between the competing foreign powers for control of Japan through the use of autonomous mecha units called AMAIMs in a conflict known as the Boundary War. By 2061, the war has long ended, but Japan remains divided into four occupied regions. Amō Shiiba is a young orphan who is slowly rebuilding an abandoned AMAIM he found. While scavenging for parts, he comes across an AI core containing an autonomous AI calling itself Gai who requests Amō save him before his battery runs out. Amō plugs Gai into his salvaged AMAIM, and Gai begins rebuilding it and learns it is a rare manned model called Zenbu. Meanwhile, Oceanian mercenaries falsely accuse Amō and his scavenger friends of terrorism, forcing him to pilot Zenbu to destroy the AMAIMs sent after him.