A routine test involving the EVA pilots turns into a struggle for survival when a wholly new type of Angel appears and spreads inside NERV HQ. This new, computer-like angel threatens to set off the self-destruct for the entire facility, leaving Dr. Ritsuko Akagi in a race against time to save the GeoFront and destroy the Angel.

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.

Shinji beats Asuka in a synch test, much to her annoyance. Not too long after, the EVAs are dispatched to deal with a mysterious apparition, and EVA-01 is sucked into a shadowlike blackness that materializes out of nothingness from under it. While an emergency operation to rescue the captured EVA is concocted, Shinji goes on a trip into the depths of his own consciousness...

Evangelion Unit-03 arrives from the United States. However, its activation experiment brings out NERV's worst nightmare when it turns out to have been infected by the Thirteenth Angel. The other EVAs are dispatched to battle the Angel-infected abomination... even at the risk of killing its helpless pilot.

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 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.

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.