Marvel Studios has been keeping quiet about everything related to Avengers: Endgame—so much so that even the official trailers and teasers for the film may not show any scenes past the first 20 minutes of the movie. As a result, fans have desperately been watching (then re-watching) the previous films and the new trailer to see if they can pick up on any plot giveaways.

One of the most popular rumors making the rounds is that in order to reverse the death and destruction that Thanos brought down on the Avengers in Infinity War, there will need to be some sort of time travel involved in the new film. Now, a pair of cast listings have added fuel to the theory’s fire. The movie’s cast listing on IMDb pretty much confirms there will be scenes from the 1970s, with actors slated to play the roles of “'70s Car Girl #1” and “'70s Scientist/Lab Worker.”

Of course, we can't say for sure whether those ’70s scenes will be flashbacks or the Avengers traveling back in time to search for ways to defeat Thanos, possibly with the help of Captain Marvel. (Also adding credence to the theory is the fact that Captain Marvel star Samuel L. Jackson just dropped a major spoiler when he said that Brie Larson's character is "one of the few people in the Marvel universe that can time travel.")

Regardless, any scenes set in the '70s will likely feature Tony Stark and his family, as Tony was born during the early ’70s and his father, Howard Stark, worked on arc reactor technology during the decade. Actor John Slattery, who played Howard in previous Marvel films, was reportedly seen on set during reshoots, which seems like a pretty solid tip-off.

Avengers: Endgame will arrive in theaters on April 25, 2019.