How Far Will God Test Us?

Viral finds dark humor in humanity's liberator and a beastman traitor rotting in the same prison, while Simon frets over the two weeks left before the moon comes down. A wingless bird beastman corners Simon in the locker room, blaming him for Cytomander's defeat and the loss of his wings; Viral kicks the assailant into a wall and taunts Simon, stripped of his mech, his woman, and his comrades, for failing to defend even himself. Goaded into a brawl, Simon trades blows with Viral, who heals a punctured hand on the spot and credits the deathless body Lordgenome granted him. He demands to know whether doing nothing truly counts as duty, likening Simon to Lordgenome, before guards separate everyone into different cells.

Leeron shows Rossiu a simulation with a brutal conclusion: the impact will destroy surface settlements and underground shelters alike, and superheated gases will render the planet unable to sustain life for a full year. The Arc-Gurren must therefore wait out that year in space. Lordgenome's head is wired into the ship's Spiral Engine, which activates successfully. Aboard the vessel, Kittan notices animals being loaded, shakes answers out of Guinble, and is shown the same simulation. He rages at a plan that writes off so many lives and proposes smashing the moon instead, but Rossiu replies that a failed attempt guarantees extinction, that his aim is saving every life he can, and that hard choices define a leader. Kittan accepts the logic without forgiving it. Dayakka, it emerges, has resigned his post to stay with his family, and Kittan visits his niece Anne in the hospital.

The Mugann descend on Kamina City and hammer Parliament Tower in a bid to destroy the Spiral Engine. Grapearls counterattack while Kittan fights from the ground with a rifle loaded with Spiral Shells; when a beam bears down on him, Makken's Mo-Shogun blocks it, and Leyte rolls in with Team Dai-Gurren's original Gunmen, never scrapped after all and now bristling with spiral weaponry. The Arc-Gurren surfaces behind a Spiral Shield that Lordgenome warns can hold only thirty minutes without draining the power needed for launch. As Grapearls ferry evacuees aboard, Kittan tells Rossiu he is finally acting like a leader should, then asks for the Core Drill; Rossiu hands it over, and King Kittan streaks away to return it to Simon. When the timer expires, the ark ascends, leaving crowds of citizens below.

At Lincarne Prison, Simon tells Viral he can accept dying so long as the people stay safe. Nia appears to both inmates, shows them that nothing on the planet will survive the collision, and accuses Rossiu of abandoning humanity, repeating that the Anti-Spirals require absolute despair. A warning shot cuts her off, fired by an old friend: Yoko.

The biocomputer is connected to the Arc-Gurren's Spiral Engine, and the Mugann damage Parliament Tower trying to reach it. Team Dai-Gurren's Gunmen prove to be intact and upgraded with spiral weapons rather than scrapped.

The Arc-Gurren launches with thousands of Kamina City residents left behind, Rossiu entrusts the Core Drill to Kittan, and Yoko returns at the episode's close.

The Japanese title, Kami wa Doko Made Bokura o Tamesu, matches the English broadcast title How Far Will God Test Us?. It aired in Japan on August 11, 2007, and in English on October 13, 2008, between Episode 19 and Episode 21.

The prison fight establishes Viral's immortality, a gift from Lordgenome that becomes relevant through the rest of the series, and marks the point where Viral begins treating Simon as his rival rather than Kamina.