"Crisis on Infinite Earths" Cleans Up an Arrowverse Continuity Error

Remember the terrible future timeline from the first season of DC's Legends of Tomorrow, where Star City was a horror show and Oliver Queen (Stephen Amell) was presumed dead, only to come out of retirement in time to meet the Legends in "Star City 2046?" Well, if you're a Legends or Arrow fan, you have probably talked about it at least once in the last couple of years. Between Zari Tomaz (Tala Ashe) coming from a very different 2040s than that one and Arrow's flash forwards revealing a different future for Star City and Oliver, fans have been wondering when the other shoe was going to drop.

And drop it did -- in the first part of "Crisis on Infinite Earths," which aired as tonight's episode of Supergirl. While the spoilers that follow are pretty minor, they are spoilers, so beware.

At the start of the episode, Superman (Tyler Hoechlin) and Lois Lane (Elizabeth Tulloch) of Earth-38 discover that an antimatter wave is moving through space, destroying everything in its path. Jonathan Kent, their new baby, is placed in an escape pod and blasted off on a trajectory towards Earth, just like his father was at that same age, and the antimatter annihilates Argo City, where they have been living since last year's "Elseworlds" crossover, killing all the remaining Kryptonians except for Kara (Melissa Benoist).

Not long after that, Clark and Lois are brought to Earth alongside Harbinger (Audrey Marie Anderson), the current-day Oliver, Mia Smoak (Katherine McNamara), and Batwoman (Ruby Rose). It turns out that their haste to save Jon was for nothing, as Harbinger came to recover Superman as the Crisis began on Earth-38. Because they had blasted him off, though, his pod ended up being shunted through the multiverse, landing on Earth-16 instead of its planned Earth.

On that world, he lands in -- you guessed it! -- Star City, in the year 2046. Besides explaining the continuity flub -- somehow the season one Legends, maybe because they weren't especially experienced at using the Waverider or something, moved through the multiverse as well as time -- it also gives Sara Lance (Caity Lotz) an opportunity to have a meaningful exchange with the Oliver of that world, essentially communicating how much our Oliver means to her by telling him how much better Earth-1 is than his doomed universe.

"It was really important to me that Sara have some really significant moments with Oliver, in the beginning of this crisis, in order to remind the audience how far they go back, and how embedded her history is with his, and how important he is to her in her life and where she's ended up," Arrow showrunner Beth Schwartz told reporters during a screening of hours one and two of "Crisis" earlier this week.

The irony that they waited until "Crisis on Infinite Earths" to do this -- since the comic book miniseries of the same name was used as a massive, line-wide continuity clean-up -- is likely not lost on the producers.

"Crisis on Infinite Earths" kicks off tonight -- Sunday, December 8 -- on Supergirl, runs through a Monday episode of Batwoman and that Tuesday's episode of The Flash. That will be the midseason cliffhanger, as the shows go on hiatus for the holidays and return on January 14 to finish out the event with the midseason premiere of Arrow and a "special episode" of DC's Legends of Tomorrow, which launches as a midseason series this year and so will not have an episode on the air before the Crisis.