Ep 1. Earthengine Open Fire

Captain Earth follows a high school student named Daichi Manatsu, who witnesses a mysterious rainbow circle in the sky that leads him to a secret organization called Globe. Globe reveals to Daichi the existence of a massive, sentient AI known as the Planetary Gear, which seeks to destroy the Earth. However, Globe also has a weapon to combat the Planetary Gear - the Earth Engine, a giant mecha that requires pilots who possess unique abilities known as "Livlasters".

In the first episode, titled "Earthengine Open Fire", we see Daichi as a young boy, driving with his parents. Suddenly, they spot a strange rainbow circle in the sky - a phenomenon that Daichi will later learn is connected to the threat of the Planetary Gear. The episode then jumps ahead in time to Daichi in high school, where he is contacted by Globe and recruited to become a pilot of the Earth Engine.

Daichi arrives at Globe's headquarters, where he meets his co-pilots - the stern and serious Teppei Arashi, and the cheerful and flirtatious Hana Mutou. Daichi then undergoes a test to determine his compatibility with the Earth Engine, and impresses Globe with his abilities as a Livlaster. However, Daichi also learns that his father was one of Globe's top researchers, who died while working on the Earth Engine project. Daichi is haunted by his father's death, and feels a personal responsibility to help prevent the destruction of the Earth.

As Daichi and his team prepare for battle against the Planetary Gear, they encounter a new threat in the form of a mysterious red-haired girl who seems to be connected to the enemy. Daichi recognizes her as the same girl he saw during the rainbow circle sighting as a child. Meanwhile, the Planetary Gear launches an attack on a massive oil tanker, forcing the Earth Engine team into action.

The majority of the episode is dedicated to the intense, action-packed battle scene between the Earth Engine and the Planetary Gear, with Daichi and his team fighting to protect the tanker and its crew. The animation is stunning, with vibrant colors and fluid movement that showcase the power and agility of the Earth Engine.

"Earthengine Open Fire" does a great job of introducing the world and characters of Captain Earth, while also setting up the larger conflict between the Earth and the Planetary Gear. The episode is a strong start to the series, with exciting action, compelling characters, and deep emotional stakes. Viewers are left eager for the next episode, curious to see how Daichi and his team will continue to fight against the alien threat.