'Arrow,' 'The Flash,' and 'Legends of Tomorrow' All Have Unfinished Business in the 2040s

Tonight on The Flash, Nora West-Allen (Jessica Parker Kennedy) headed back to 2049 again, reminding fans that the near future contains the key to some of this season's (and probably next season's) biggest mysteries.

This is pretty normal for The Flash, a show where time-travel has been baked into the narrative since the first time Barry (Grant Gustin) time-traveled to prevent a tsunami. The fact that Barry and Iris's (Candice Patton) daughter (born somewhere between 2019 and 2024) is a major character this season means that the 2040s, her "home" decade, will help shape her story.

The biggest difference between this season and previous ones is that Arrow has a flash-forward story, meaning that the 2040s are actually very important to that series' narrative as well.

The flash-forward story takes place in 2040, and centers on Roy Harper (Colton Haynes), Dinah Drake (Juliana Harkavy), and Zoe Ramirez (Andrea Sixtos) trying to hunt down an explosive device that might destroy the city. Star City and The Glades have swapped roles, with Star City now crime-ridden and The Glades wealthy, crime-free, and techologically advanced. There is a deep-rooted hatred of costumed vigilantes on the part of many of the city's denizens, including Mia Smoak (Katherine McNamara).

How they got there is anybody's guess, but the dystopian, crime-ridden, and superhero-averse 2040 of Arrow season 7 feels like it would be right at home as a precursor to the 2042 seen on season three of DC's Legends of Tomorrow.

There, Zari Tomaz (Tala Ashe) and her family were part of a resistance to a totalitarian regime headed by ARGUS, who jailed or killed dissidents. Zari's brother was murdered and her parents' whereabouts are unknown.

Tonight's episode of The Flash, "Cause and XS," shares a high concept with last season's "Here I Go Again," an episode of Legends of Tomorrow that centered on Zari. In the episode, Zari designed a program that would allow Gideon (Amy Pemberton) -- the Waverider's on-board AI -- to search the timeline for loopholes that would allow her to alter the timeline and save her family.

According to Gideon at the end of the episode, every version of the timeline that allowed such a change involved Zari continuing to be a part of the Legends. Ultimately, Sara Lance (Caity Lotz) agreed to let Zari try to change her past, since it is the rest of the Legends' future.

Zari is not the only one who wants to change the 2040s by superheroing in the present: that is why Nora is in 2019, too. She hopes to prevent Barry from dying in "Crisis on Infinite Earths" (something that seems doomed to fail). And while Team Arrow have not yet begun to contemplate time-travel as a potential solution for their problems, it seems difficult to imagine that when the Crisis moves forward from 2024 to 2019, it won't have a domino effect on the 2040s, changing the present and future of every series that takes place on Earth-1.

Arrow airs on Monday nights at 8 p.m. ET/PT, before episodes of Black Lightning on The CW. The Flash airs on Tuesdays at 8 before episodes of Roswell New Mexico. DC's Legends of Tomorrow is currently on hiatus. The series will return on Monday, April 1 at 8 p.m. ET/PT, with Arrow moving to the 9 p.m. slot to accommodate the change.