SPOILER WARNING: This article contains major spoilers for "Elseworlds, Part 1," the first installment of this year's Arrowverse crossover.
When it comes to fighting the Monitor, the heroes of the Arrowverse are going to need all the help they can get. Fortunately, Batwoman will be there to lend a hand when they turn up in Gotham for some answers. While it's certainly been no secret that she'll join forces with him, their reason for heading to Gotham has been kept under wraps. Now, "Elseworlds, Part 1" has revealed why they're headed to Bruce Wayne's hometown.
Over the course of the episode, Oliver and Barry attempted to convince Team Flash that they had somehow swapped lives. Naturally, Team Flash wasn't so easily swayed. After a few mishaps -- including the team throwing Barry and Oliver into the Pipeline -- Barry was able to convince Iris he was telling the truth. Soon after, Cisco also bought into their story, but for a very different reason: he had Vibed the Monitor.
Initially, Cisco Vibed the Monitor when he was by himself. He saw only flashes of the Monitor, who warned him not meddle in his plan. This disturbed Cisco so deeply he didn't mention it to the team, at least until Iris revealed she let Barry and Oliver go because she believed them.
Later, Cisco brought Oliver, Barry and Kara in on his Vibe. This time, he brought them back to the Monitor's meeting with Arkham Asylum doctor John Deegan, where the Monitor handed Deegan to power to rewrite reality. This time, however, the Monitor seemed aware that Cisco was watching and spoke directly to him, issuing him another warning before severing the connection.
As Cisco stepped away to recover, Oliver did a quick sketch of the scene they had beheld. While Barry and Oliver said they didn't recognize the new villain, Oliver pointed out the skyscraper in the background: Wayne Tower. As such, they realized they needed to go to Gotham, as that was where all their troubles had started.
This year's Arrowverse crossover event will involve the casts of Supergirl, Arrow, and The Flash. The event will unfold over three nights, starting with a special episode of The Flash on Sunday December 9 at 8 pm ET/PT. Then, it continues Monday, December 10, with Arrow, and concludes on Tuesday, December 11, with Supergirl.