Squad 13 returns to Garden, to the place where they were made, even if it isn’t where they came from—a question Kokoro ponders while doubting the adults’ answers. In narration, Hiro says it doesn’t matter where, as long as he can live life to the fullest. But his increasingly distant (and feral) partner Zero Two feels the opposite: where she came from—what she is—means everything.
Hiro the rest of the squad are only tagalongs. The reason they’re at Garden is for Zero Two, or “Iota”, as the leader of the elite “Nines” calls her. He’s surprised she’s been able to integrate so well into a squad of humans, and is rudely explicit about how inhuman she is, gaining the ire of Ichigo. Ultimately the adults’ patience with Zero Two’s sullen bit runs out and they have to tranq her.
The rest of the squad tours the Garden, even though they were forbidden from doing so, and the memories come flowing in. Hiro, for one, vageuly remembers a red girl with white hair and horns. They see children getting parasite injections far earlier than they did.
With the increase in klaxosaur activity, it would seem humanity no longer has time for experiments in disobedience or individuality; they’re basically growing bodies to put into cockpits as fast as they can. Squad 13 is a relic; an indulgence they can no longer afford…even though it could be argued they bear elements of humanity crucial for its long-term survival.
As humanity hopes continuing to refine their children into increasingly efficient parasites will help extend the time they’re on the planet, Zero Two insists her time is quickly running out. Every time she sorties with Hiro she tries to kill as many Klaxosaurs as possible, as viciously as possible, hoping it will help her become human.
Because Hiro believes everything in this show is about him, he assumes Zero Two feels like she can’t truly belong in the squad, or in his heart, unless she becomes completely human, shedding everything that made her part klaxosaur. Since Gorou and Futoshi’s feelings helped him understand his own, he thinks confessing his love for Two will both appease and please her.
Imagine my combination of delight and despair upon witnessing Hiro completely strike out after confessing to the person who always insisted on calling him her “Darling”, not to mention kissing him and staying by his side. Hiro drops the Darling and calls Hiro “fodder.” She only cares about him if she can use him to kill klaxosaurs.
Since partnering with Hiro, we learn Two’s level of “saurification” has been steadily rising, which explains why she’s been acting so feral lately. (Ichigo hears this, because the adults apparently have an open-door policy.)
When she learns what is becoming of Zero Two, which she adds to the knowledge given to her by the leader of the Nines, Ichigo moves to have another conversation with her squadmate, only to find her smashing mirrors to bits for daring to reflect her face. Ichigo freezes in terror and closes her eyes, ready for the worst, but Two just walks past her.
Despite her clear and worsening imbalance, the adults continue to let Zero Two sortie with Hiro, and Two continues to believe she can become human if she kills enough klaxosaurs. Whether someone told her such a theory was true, or she simply decided for herself it was true, the evidence just doesn’t bear out that outcome.
If anything, killing klaxosaurs only seems to increase her bloodlust for combat. When Hiro tries to hold her back, she eventually overloads and starts to choke Hiro, while more and more images of the red girl with horns flash through his head. This totally berserk Two wants to meet her darling from “back then.” I imagine we’re in for some crucial flashbacks at the start of the second half.