TV Episode | TV-14 | | Action, Adventure, Crime
The gang comes together for Barry and Iris's wedding, but the ceremony is crashed by villains from Earth-X.
Felicity referred to Oliver Queen of Earth X as "Oliver in the High Castle" a reference to the television series and novel, Man in the High Castle, which also depicts a world where the Nazis won World War II similarly, the television adaptation explored alternate dimensions in its second season.
You were a good man here. And I believe that you still can be.
Tommy Merlyn: No. You don't understand. If I - If I talk, if I break, the fuehrer will kill my father. He'll kill my mother, everyone that I love.
Oliver Queen: I will not let that happen. I will stop him.
Tommy Merlyn: Do you ...
Kara finds out that Oliver has kryptonite arrows in his inventory. The logistics of this are hard to explain as the substance does not exist on Earth 1, and Team Flash is in possession of the only means of travel to Kara's universe. This means Oliver would need their help in obtaining kryptonite. Moreover, all the kryptonite on Kara's Earth was given to Superman to secure, making it even more unlikely that Oliver would have been able to acquire it. Lastly, Kara is personally offended when she finds out Lena Luthor has kryptonite, but she is far less upset with Oliver for possessing it.
The usual opening narration and title card are replaced by a special "Crisis on Earth-X" sequence.