Last week, Zacian and Zamazenta defeated Eternatus at Hammerlock Stadium. Eternatus was attacking the stadium and causing Pokémon to rampage.
Eternatus broke out of the sphere where it was being held in captivity. The Pokémon emitted red lights causing Pokémon throughout Galar to Gigantamax and go on a rampage.
Chairman Rose realised that Galar particles could be used as a new Galarian energy source. “Eternatus generates limitless Galar particles,” stated Chairman Rose. This is why he renamed the Darkest Day, Eternatus and restored it.
After learning that Zacian and Zamazenta created the downfall of the Darkest Day in the past, Sonya and Goh explored the Slumbering Wield. There, echoes of Zacian and Zamazenta led them to a sword and shield.
Goh and Sonya travelled to Hammerlock Stadium where Leon and Team Rocket were unable to Gigantamax their Pokémon against Eternatus. Throughout these events, Eternatus gathered Galar particles in preparation for its final form.
After entering its final form, Eternatus was not affected by Pikachu’s Thunderbolt, Lucario’s Aura Sphere and Cinderace’s Pyro Ball. In response, the spiralling Pokémon sent out red beams, dealing major damage to all three of its opponents.
As Ash and Goh fought the Darkest Day, the sword and shield glowed. This led Ash to wonder if these were in fact the legendary sword and shield. Ash held aloft the glowing-blue sword and Goh held the glowing-red shield. Goh declared, “All we can do now is become the legends ourselves.” Subsequently, the sword and shield summoned Zacian and Zamazenta and floated up into the air. They changed the wolf-like Pokémon into Zacian’s Crowned Sword and Zamazenta’s Crowned Shield forms.
The two legendary Pokémon proceeded to attack, followed by Pikachu, Lucario and Cinderace. Zacian and Zamazenta made a heroic charge causing the defeat of Eternatus. Goh then caught Eternatus with a Pokeball.
Following the capture, the two legends vanished and all of the rampaging Pokémon returned to normal. To Ash and Goh, Leon stated, “I think you’re the legendary heroes.”
Chairman Rose’s location is currently unknown. Eternatus is dormant and in an underground vault. There is no evidence it will not wake up, so a professor —Sonya’s grandmother— said that countermeasures must be researched.