Shinji Ikari is summoned to Tokyo-3 by his estranged father Gendo, commander of the special agency NERV, to defend the city from a giant Angel by piloting the only weapon capable of battling the monster: Evangelion Unit-01.

EVA-00 is finally repaired, and Shinji tries to get to know its enigmatic pilot, Rei Ayanami, better. However, he is confounded because she is extremely insular, has no friends at all, and the entire record of her past has been erased. In the midst of this, a very powerful Angel, the floating monolith Ramiel, attacks Tokyo-3.

Ritsuko briefs Shinji on the real nature of Second Impact, the Angels, and the Evangelions' mission to defeat them. Misato and Ritsuko attend the public demonstration of a new Angel-fighting robot, Jet Alone, built by a rival defense contractor to NERV. However, the nuclear-powered robot quickly runs out of control, and Shinji must use EVA Unit 01 to load Misato onto Jet Alone so she can she can enter in its automatic shutdown code, before it melts down in a nuclear explosion.

Asuka joins Shinji’s class at school, and moves in with Misato and him in their apartment. As Asuka adjusts to Japan (or rather, everyone else adapts to her...), a new Angel attacks which is capable of splitting itself into two identical copies. EVA-01 and EVA-02 are defeated, and NERV is publicly humiliated. With the Angel in a week-long regeneration period after an N² Mine attack by the JSSDF, Asuka and Shinji must learn to "synchronize" with each others movements combat, in order to defeat it once and for all.

It seems like it's an important day for nearly everyone at NERV. Misato and Ritsuko are going to a wedding; Shinji and Gendo are visiting Yui's grave; Asuka has a date. However, important things will spring from these seemingly mundane events.

Enraged over Touji's near-death at the hands of his own EVA, Shinji refuses to pilot an Evangelion again and prepares to leave Tokyo-3 for good. He is forced to reconsider that decision when an immensely destructive new Angel attacks just as he is about to leave...

Asuka's synch rate is on a downward spiral after her defeat at the hands of the Fourteenth Angel, Zeruel, and her frustration with Rei, Shinji, Misato and Ryouji is on the rise. Angrier and more disturbed than ever, she is forced to relive her dark, traumatic past during the encounter with the Fifteenth Angel, Arael.

Asuka sinks into deep depression after Arael's mental probing, and is unable to pilot when the new Angel Armisael arrives. Armisael begins physically fusing with EVA-00 and threatens to do the same to EVA-01, prompting Rei to sacrifice herself to save Shinji, only to appear alive soon afterwards.

Too frightened to face Misato or Rei, Shinji runs away yet again, only to meet and strike a friendship with Kaworu Nagisa, the replacement pilot for EVA-02. Kaworu's openness and friendliness provide much-needed comfort for the disturbed Shinji. However, suspicions abound over Kaworu's incredible synchronization abilities.

Instrumentality has begun, and now its inner process, the joining of all souls into one, will be depicted. The episode is primarily driven by dialogue, the background usually complete darkness. White text often appears on a black screen, an omniscient voice questioning the characters.

Instrumentality continues. The focus is primarily on Shinji now, as he learns to accept the individual’s ability to shape their world, and how the self cannot exist without others to define it.