Supergirl Recap With Spoilers: Worlds Will Live and Worlds Will Die as "Crisis on Infinite Earths: Part 1"

"Crisis on Infinite Earths" arrives for the Arrowverse tonight and it begins on Supergirl's Earth-38 with the heroes coming together to fight for the fate of all realities as an anti-matter wave threatens to destroy it all. It's an event that as been very eagerly-awaited for fans of The CW's connected universe of DC TV shows and now, years after it was first teased on The Flash's series premiere in 2014, "Crisis" is finally here. Read on to find out how the first night of "Crisis on Infinite Earths" played out.

Spoilers for tonight's episode of Supergirl, "Crisis on Infinte Earths" Part 1," below.

The crossover opens with a montage showing the heroes of the Arrowverse being heroes, followed by the red skies signaling the crisis on various Earths, including Earths representing the 1989 Batman film, DC Universe's Titans, and even the 1960s Batman television show. Sadly, those worlds are eliminated by the wave of anti-matter that strikes them.

On Earth-38 Supergirl and her allies at the DEO are dealing with global earthquakes and quickly realize that the danger headed towards them from outside of Earth and, more than that, is going to hit Argo City first, a terrifying prospect as Clark and Lois live there with their infant son, as does Kara's mother, Alura. As Clark and Lois tend to baby Jonathan, Brainy and Kara try to warn them, a warning that arrives just as the red skies do. With just a few moments before the world will be destroyed, Alura guides the Kents to a pod and they send baby Johnathan to Earth just before Argo is destroyed. On Earth, Supergirl watches Argo's signature disappear.

Meanwhile, Lyla – now the Harbinger -- gathers various heroes including Oliver Queen, Mia Smoak, Barry Allen/The Flash, Sara Lance, Ray Palme, and Kate Kane/Batwoman. She brings them, along with Clark, and Lois who she saved from Argo to the DEO on Earth-38 at the request of The Monitor. They are tasked with protecting a Quantum Tower in National City, a structure which can hold off the crisis and may be their only hope. It's confirmed that Alura is among those lost on Argo, but Kara manages to comfort Clark and give him hope despite her own great loss.

The group then realizes that Jonathan somehow ended up on Earth-16 in the year 2046. Sara, Brainy, and Lois go to get him and find that the baby was discovered and saved by the Oliver Queen of that world. He lost his Sara on the Gambit, and Earth-1 Sara explains all that the two of them gained on her world as a result of them being on the ship. She, Lois, and Brainy bring the baby home.

Meanwhile, J'onn appeals to all the aliens on Earth to use their ships to help evacuate the humans to Earth-1 in the event that the heroes are unable to defend the Tower. Alex pleads with Lena to help build the tech they need to bring that many people through the multiverse to safety. Lena agrees and the women work well together, but Lena does not forgive Alex.

As the heroes prepare to defend the Tower, Oliver gives Mia her own Green Arrow suit before talking to Barry. He is shocked that Barry says he is going to die in the Crisis, and Ollie confronts the Monitor since the deal in "Elseworlds" was that his death would save Barry and Kara. The Monitor says it did during their last encounter, but this is something new. A greater crisis.

The heroes go to the Tower to protect it and are set on by a massive number of Shadow Demons. Supergirl and Superman also use their heat vision to keep the Tower working so as to give time for the evacuation, but eventually the tower starts to fail. The Monitor starts sending the heroes to Earth-1 so they can regroup for the next fight, but Oliver refuses to stop fighting while people still need to be evacuated. Eventually he is overwhelmed by the Shadow Demons.

The Monitor brings the dying Oliver Queen to the other heroes safely evacuated to Earth-1 to say his goodbyes. He tells them that the hero was not supposed to die yet nor die in this way, but that 3 billion people were evacuated to Earth-1 before Earth-38 was destroyed and Oliver's sacrifice in staying behind saved a billion lives. Oliver says his goodbyes to his friends and loved ones and then dies.

As Oliver is dying, Nash Wells appears only now he is Pariah, punished for releasing the Anti-Monitor by being forced to watch his destruction.

Additional reporting by Emily Donn