In year 70 of the Cosmic Era, tensions between the Earth Alliance and ZAFT, the organization representing the genetically engineered Coordinators living in orbital research and manufacturing stations called PLANTs, have escalated into full-scale war after one of the PLANTs was destroyed by a nuclear warhead.
On the space colony Heliopolis, territory of the neutral nation Orb, Kira Yamato and his friends are attending a technical college. While they work on a special project for their professor, a mysterious visitor waits in their lab to see him. However, an Earth Alliance warship has just docked at Heliopolis, pursued by two ZAFT vessels — the Vesalius (under the command of the blond, masked man Rau Le Creuset) and its escort the Gamow. Despite confidence on the part of both the Earth Alliance officers and Heliopolis officials that they're safe in neutral territory, Rau launches an attack. ZAFT commandos infiltrate the colony, preventing most of the Earth Alliance vessels from mounting a defense by destroying the port facilities where they are docked with explosives. Only one Earth Alliance ship is able to launch; aboard is Ace Pilot Mu La Flaga, who attacks the ZAFT mobile suits in his Mobius Zero Space Fighter.
Meanwhile, the commandos have found their targets: the Earth Alliance's prototype mobile suits constructed in Heliopolis. Earth Alliance Lieutenant Murrue Ramius and her men, in the process of moving the mobile suits from the factory to the port, comes under attack by ZAFT mobile suits and commandos simultaneously. The battle causes much collateral damage inside the colony — including damaging the building Kira and his friends are in. They start to evacuate the building, but the professor's mystery visitor runs off alone rather than leaving the building. Kira follows, becoming separated from his friends. The building receives further damage while they argue, and Kira realizes — contrary to his initial assumption — that the visitor is in fact female. He manages to convince her that they need to evacuate to the nearby shelters in the factory district. Upon arriving there, however, they discover two of the Earth Alliance's prototype mobile weapons in the midst of being moved. The mystery visitor makes a cryptic comment about her father having betrayed everyone. The noise draws the attention of Murrue, who very nearly shoots them before realizing that they're just local kids.
Elsewhere, three of the ZAFT commandos — Yzak, Dearka, and Nichol — have successfully hijacked three of the Earth Alliance prototypes, and retreat back to the Gamow. They expect two more, Athrun and Rusty, to have little trouble collecting the remaining two prototypes that are still in the factory district. Kira and the mystery visitor make it to a shelter in the factory district, but it's filled to capacity. Kira convinces them to let the visitor inside, and heads for a different shelter. On his way there, he ends up embroiled in the gun battle between the ZAFT commandos and the Earth Alliance soldiers. Rusty is killed and Murrue wounded, but before Athrun can finish her off, he hesitates because he recognizes Kira, which gives Murrue time to drive him away. As Athrun retreats, Murrue drags Kira into the nearest prototype's cockpit with her and activates it.
Tropes used in this episode:
- Bifauxnen: The professor's mysterious visitor.
- Falling into the Cockpit: Happens to Kira right at the end of the episode.
- Grand Theft Prototype: How ZAFT kicks off the series, by stealing the Earth Alliance's Gundams. Four were successfully taken, but the last pilot died when Murrue shoots him and she and Kira enter the last Gundam's cockpit.
- Opening Narration: The prologue narration describes the rising tensions between Earth and the PLANTs, and the all-out war that followed:"Year 70 of the Cosmic Era. After the Bloody Valentine tragedy, tensions between Earth and the PLANTs quickly escalated, throwing from animosity to full-fledged war. Earth's dominant military was meant to crush the PLANTs, heralding a victory within just a few days. But, that victory never came. Eleven months have passed now since the Bloody Valentine tragedy, and there is no end in sight."
- Ordinary High-School Student: Kira and his friends, though it's a "technical college" rather than a high school. Presumably the Heliopolis educational system has students start college between 15 and 17, or given that Kira is a Coordinator he got moved up a few grades.
- Super Prototype: The Gundams.
- Truce Zone: Heliopolis is presented as one, but it doesn't last.
