Far away… In a system so distant that the light from its stars will never reach Earth… A war was drawing to a close...

Exelica and Crueltear—humanoid weapons system called Triggerhearts developed by C.H.I.L.D.A., an interplanetary defense organization—were sent to join the fight against the autonomous combat unit known as the Ver’mith.

In the midst of the battle, just as they had taken the upper hand over the Ver’mith, Exelica and Crueltear were accidentally sent to Earth using an emergency teleportation gate activated by the Ver’mith.

Finding themselves on an unknown planet and without the strength to return home, the injured Triggerhearts were despondent as they did not even have the means to learn the outcome of the battle.

They had just about recovered from their wounds and had finally begun to consider Earth as a haven… when it happened.

A nightmarish vision filled the sky. The remains of the Ver’mith forces had arrived. The gate had re-opened…

Although the Ver’mith forces had departed at the same time as Exelica and Crueltear, the gate’s instability had caused a lag in their arrival.

The Ver’mith had chosen Earth as their new base of operations. The invasion had begun. Exelica and Crueltear knew they had no choice but to fight to protect their new home.