Cast member Chris Evans poses at a press line for the movie "Avengers: Age of Ultron" during the 2014 Comic-Con International Convention in San Diego, California July 26, 2014.
Cast member Chris Evans poses at a press line for the movie "Avengers: Age of Ultron" during the 2014 Comic-Con International Convention in San Diego, California July 26, 2014. Reuters/Mario Anzuoni

Marvel recently unveiled the working title of "Captain America: Civil War." It will reportedly be known as "Sputnik." The revelation has led to a frenzy of speculations about the plot of the "The Winter Soldier" sequel. Here are some of the theories floating around. [Warning: Potential Spoilers Ahead!]

Comic Book Movie picked up the news about the production title of "Captain America: Civil War" from Production Weekly. The writer of the CBM report further speculated on what could be the meaning of "Sputnik" in context of the movie's plot. It is noted that giving such titles to the movie in production is a very common practice. It is said that these titles may hold "subtle references to certain minor aspects of the movies."

The term Sputnik is a Russian word used to refer to the first earth satellite sent by Soviet Union into the space in 1957. Does the term have any association with Marvel Universe? The website states that Sputnik is the name of a Marvel Comics character. The said character made his first appearance in "Captain America #352" as created by Mark Gruenwald and Kieron Dwyer. The character subsequently assumed the personality of Vostok. He figured in "Avengers#319-324," "Incredible Hulk #393" and other comics. He was also one of the members of a team of Russian superheroes, the Supreme Soviets.

Furthermore, the abovementioned publication points out that the term "Sputnik" was also used as a "'shutdown code' against the Winter Soldier/Bucky Barnes" by Captain America assassins in the "Death of Captain America" storyline. This was fed into his mind by the Soviets, which led to Winter Soldier to "take on Crossbones, S.H.I.E.L.D. and Avengers" and ultimately resulting in Steve Rogers/Captain America's death.

However, in the absence of official confirmation, it is wise to consider all this as mere speculations. It remains to be seen what actually happens in the third instalment of "Captain America." However, if "Sputnik" is involved, then Sebastian Stan's Bucky Barnes/Winter Soldier will have an important and larger role to play in the "Captain America: Civil War" storyline.

Meanwhile, the return of Bucky Barnes has been confirmed by Marvel in late August, as revealed by Movies.com. Anthony and Joe Russo will be helming the Chris Evans, Robert Downey Jr. and Chadwick Boseman starrer "Captain America: Civil War." The film is expected to hit the theatres on May 6, 2016. The movie is set to start filming in early spring in locations such as Atlanta and Georgia.