Starting from the beginning, a great threat looms over Pace-1 planet: after a mysterious explosion, a piece of Letrametal travels at supersonic speed towards the planet. The impact is imminent and it will be catastrophic. The Letrabots don’t know what to do to stop it!

There’s a legend: it’s said that the Letrabots can join in a super powerful robot, the Combo Big Robot ADE, but the risk of not making it is high.

Will they manage to transform and save the planet?