On April 19th, 1973, a race of extra-terrestrial lifeforms launched a landing unit from the moon, which touched down on Earth, in central Asia. Ever since, mankind has been engaged in a losing war against this alien species, known as the BETA, as they have gradually expanded outwards across the globe. After 20 years of non-stop fighting, the war has reached the shores of Japan...

Shirogane Takeru found himself inexplicably transported to a world that resembled his own in many ways, with one major difference: For nearly 30 years, mankind has been at war with the alien BETA, who have succeeded at wiping out over half of humanity and had nearly captured the entire Eurasian continent. As Takeru tried to come to grips with this bizarre new reality, he realized too late tha...

As Takeru starts to feel anxious about whether or not he can actually make a difference, Professor Kouzuki demands more concrete evidence of his knowledge about future events.

Takeru's efforts to change the future are starting to have an effect, as the 207th's Tactical Surface Fighters show up earlier than in the previous timeline. And if an idea he's cooking up works, it might make them even more effective weapons against the BETA.

Takeru and Professor Kouzuki have collaborated to create a new operating system for the 207th's Tactical Surface Fighters, making the anti-BETA weapons more maneuverable and responsive than ever. But will it even matter if Yuuko can't actually make some progress on the mysterious Alternative IV plan?

In order to help Professor Kouzuki fulfil her plans for Alternative IV, Takeru partakes in an experiment designed to send him back to his home world.