SPOILER ALERT: Do not read if you have not yet watched “Crisis on Infinite Earths: Part One,” the premiere of the 2019 “Arrowverse” crossover event on the CW.

The “Arrowverse” “Crisis on Infinite Earths” crossover kicked off with a bang: Oliver Queen aka the Green Arrow’s (Stephen Amell) death.

With “Crisis” finally here, Harbinger (Audrey Marie Anderson) recruited a group of heroes — including Green Arrow, The Flash (Grant Gustin), Supergirl (Melissa Benoist), Batwoman (Ruby Rose), Superman (Tyler Hoechlin), White Canary (Caity Lotz) and The Atom (Brandon Routh) — and put them on Earth-38 (where “Supergirl” is set) to try and save the day.

As the heroes realized they couldn’t save the planet, they instead opted to rescue its inhabitants, boarding them on ships in the hopes of transporting them to a different Earth. But when the fight got to be too much, The Monitor (LaMonica Garrett) appeared, transporting most of the team to safety.

However, Oliver fought back, insisting he wouldn’t leave until the planet was clear, and temporarily knocked down The Monitor to delay the evacuation. But battling alone took a toll, and gravely wounded Oliver was eventually brought back to safety, after securing another billion people’s passage off of the doomed planet.

Aware he was about to die, an emotional Oliver had a somber moment with his daughter, Mia (Katherine McNamara). Barry, who was convinced he wouldn’t come out of “Crisis” unscathed, was devastated by his mentor’s state. “I gave it all up for you and Kara,” Oliver told Barry. “I need you to be the ones to save us now.” As “Arrow” comes to an end as a series this year, in many ways the character is passing the torch to the superhero from the second-ever DC on the CW drama.

The decision to kill off the patriarch of the DC/the CW television franchise this early into the crossover was made precisely because the shows had been teasing the move for so long, says executive producer Marc Guggenheim.

“It really came off of [the 2018] ‘Elseworlds’ [crossover], which strongly suggested that Oliver was going to die,” he explains. “And then [in] the ‘Arrow’ seventh season finale we [more explicitly] told the audience Oliver is going to die in ‘Crisis.’ The dilemma that we presented to our own selves was that we spoiled our own story. So if Oliver dying isn’t the surprise, what is the surprise? The timing of him dying.”

Guggenheim says the team behind the crossover “figured the audience is expecting that Oliver would die in the climax in the fifth hour,” so they “intentionally went in the exact opposite direction.” By doing this, Guggenheim feels they accomplished two key things: “Hopefully we do surprise the audience; that’s absolutely the intention. But we also really establish the stakes going into the next four hours. ‘Wow, if Oliver Queen can die, then no one is safe.’”

But with the fate of the multiverse in jeopardy, how to move on post-Oliver is a point of contention for the remaining heroes.

“The leads all have a different take on how to grieve or handle Oliver’s death,” “Batwoman” executive producer Caroline Dries says. “Some of them believe it’s over. Some of them believe we can fix this. Some of them are not wanting to even think about it.”

The crossover picks up with “Part 2” in the “Batwoman” episode airing Monday, Dec. 9 and continues on Tuesday, Dec. 10 an episode of “The Flash” that acts as the third part of the special event. The final two episodes air in January with back-to-back episodes of “Arrow” and “DC’s Legends of Tomorrow.”

Oliver’s death “sets up a really interesting stories and conflicts between all these characters,” adds “Legends of Tomorrow” executive producer Keto Shimizu. “You get to see them all grieve together in a really compelling way.”

But Supergirl aka Kara Danvers is also now grappling with the loss of her world.

“She comes [out of this experience] wanting to try and figure out how to fix what’s happened,” “Supergirl” executive producer Robert Rovner says. “That is her journey very much with Kate for not only in the ‘Batwoman’ hour, but in the rest of the crossover.”