This is a meeting that will change destiny itself.

Present day Tokyo. High school student Aoba Watase lives an ordinary life when one day suddenly he is attacked by a mysterious bipedal weapon. But he is also then saved by a mysterious bipedal weapon.To his amazement the pilot turns out to be his classmate Hina Yumihara. She puts Aoba into the cockpit of her “Valiancer” – the bipedal weapon she is controlling and murmurs: “Dio is waiting.” In that moment Aoba is enveloped by a glaring light.

Meanwhile, in the future the planet is in the midst of a massive world war. Out on those battlefields, elite Valiancer pilot for the Alliance Jyunyou Dio Weinberg and several of his comrades in mechs battle against the Valiancer corps of the military superpower Zogilia. Dio is vastly outnumbered and the situation is dire. Just then, a mech which he thought was unoccupied displays as: “Nice Coupling Response.” And inside the cockpit is Aoba -- pulled through time from the past.

The Alliance Valiancer mother ship Cygnus has also monitored the sudden appearance of Aoba and the “Nice coupling Response” with Dio. The pair’s “Feeling Match Index” is astonishing and the crew is surprised to discover that Aoba is a “Coupler” that possesses a shockingly high Coupling Potential. In order to turn the tide, they order Dio to Couple with Aoba at once.  Though he knows that if it’s successful it will result in extraordinary performance, Dio is reluctant to couple with a stranger. However, following his orders, he communicates the Proposing Sequence to Aoba, and tells him to follow the procedure as instructed. Unable to fully comprehend the situation, Aoba decides to go ahead and do as Dio says. Their coupling is successful and with the power of the activated “Coupling System” they are able to throw off the enemy.

Aoba was born in a time of peace, Dio was born in a time of war. Their meeting across the ages will dramatically change their destinies and the entire world’s…