Murrue fends off an attacking Athrun, and throws Kira into the prototype mobile suit's cockpit before jumping in herself. She activates the machine, which Kira immediately nicknames "Gundam" based on the acronym of its operating system. Athrun steals the remaining prototype, and meets up with Miguel, a ZAFT pilot in a GINN. Athrun retreats back to the Vesalius while Miguel remains behind to capture the final prototype. His attacks fail, due to the Gundam's special "phase shift" armor, which makes it virtually invulnerable to physical damage. However, the Gundam can barely move due to its incomplete OS. To prevent Miguel from destroying them, Kira seizes the controls from Murrue, modifying the Gundam's OS on the fly as he fights. He manages to disable Miguel's GINN; Miguel bails out, but not before activating the GINN's Self-Destruct Mechanism and catching the Gundam in the blast.
In Heliopolis' port, Ensign Natarle Badgiruel regains consciousness after the explosions in the previous episode, and begins regrouping with other survivors. Outside, the Earth Alliance forces are being routed. Their warship loses control due to battle damage and crashes into Heliopolis' exterior, leaving Mu La Flaga the only remaining Earth Alliance unit outside the colony. He manages to damage a ZAFT GINN, forcing it to retreat. Rau notes his respect when informed of this, and signals a retreat of ZAFT's MS while he launches in his own personal mobile suit.
Murrue, knocked out when the Gundam was caught in the GINN's self destruct, regains consciousness to find herself being cared for by Kira and one of his friends, Miriallia Haw. Several more of his friends — Tolle Koenig, Sai Argyle and Kuzzey Buskirk — are inspecting the nearby Gundam, which has shut down after running out of power. Murrue takes exception to this, firing a warning shot in their direction to reinforce the seriousness of the situation. She explains that they've all been exposed to military secrets, and she must take them into custody until she receives other orders.
While Mu and Rau fight each other inside Heliopolis' port facilities, Natarle and her survivors gather on the Archangel, the new Earth Alliance ship trapped there by the explosion. Outside, Murrue has Sai gather parts for their Gundam, the X105 Strike. Rau and Mu break out of the harbor and into Heliopolis proper. Rau turns to attack the Strike, but Kira attaches the new parts (the Launcher Striker, featuring a small gatling gun and a large beam cannon) which recharges the batteries and reactivates its phase shift armor, preventing it from being destroyed. As this happens, Natarle launches the Archangel, blasting through the debris and entering Heliopolis' interior.
Tropes used in this episode:
- Eye Awaken: Natarle, when she wakes up alone in the Archangel.
- Mecha Expansion Pack: The Strike's ability to use them is first demonstrated in this episode, with the Launcher.
- Rapid-Fire Typing: Kira busts some out when he modifies the Strike's OS.
- Self-Destruct Mechanism: Miguel uses his GINN's when trying to take out the Strike.