AllMovie

Heero is modifying explosives at a nearby base in order to trigger his Gundam's self-destruct mechanism before the Alliance can get their hands on it. Unbeknownst to him, another Gundam is laying waste to the Alliance's recovery team, effortlessly destroying the underwater mobile suits. Lieutenant Zechs, who was working on his own recovery scheme for his superior Colonel Treize, coolly observes the battle from a distance. Meanwhile, Relena is having her birthday party, but her mind is elsewhere. Putting the pieces together, she realizes that Heero is in fact one of the rebel pilots, and the military is covering up their arrival on Earth. A chance comment from a latecomer confirms her suspicions, and she learns that Heero's heading to the military port. Back underwater, Zechs' men have moved in after the destruction of the Alliance crafts, but the other Gundam returns and makes short work of them before disabling the first Gundam's self-destruct mechanism and recovering it.