Yuta Hibiki wakes up in the home of his classmate, Rikka Takarada, with amnesia. A voice from an old computer, identifying himself as "Gridman," has a mission for him, but can he even survive the next day of school without his memories?

Yuta and his friends attempt to unravel the mystery of the city and everyone else's memories. However, more questions arise when a strange samurai arrives and tries to tamper with Gridman.

A new kaiju appears which poses a problem for Yuta and Gridman. As a result, Rikka and Utsumi are left wondering if their friend will end up long since dead, just like the other students.

Rikka and Akane are invited on a group date, but the aftermath is disastrous. Will Yuta be able to convey his feelings for Rikka before it's too late?

A field trip takes the class away from the city for some summer fun, but when trouble occurs so far from home, there's no easy way to get to Junk.

The others are finding Yuta's story hard to believe. Nobody wants to confront and ask Akane, but in the meantime, Anti has made plans of his own.

When the Tsutsujidai High School Festival is threatened, the Gridman Alliance must decide how to proceed. Some of them wonder if fighting is the only choice they have.

Life goes on when there's a break in the kaiju attacks. However, when Akane's world comes crumbling down, the Gridman Alliance might need help to battle her broken heart.

It all comes down to the line as the Gridman Alliance attempts to save Akane, but do they have what it takes to battle the monster within?