After a widely successful first few episodes, the first season of the show about Peggy Carter, Captain America's girlfriend in the Marvel Cinematic Universe, will come to an end with the "Marvel's Agent Carter" season 1 episode 8, which will feature the terrorist group Leviathan, the return of Tony Stark's father Howard and even the death of one of the show's characters.

The past episode of the show, "Snafu," saw Peggy (played by Hayley Atwell) being charged with treason and espionage after it was discovered that she was working for Howard Stark (Dominic Cooper) alongside his butler, Jarvis (James D'Arcy), but she is ultimately cleared before the start of the "Marvel's Agent Carter" season 1 episode 8 - though things were left hanging in the previous episode.

As TV Equals recaps, the beginning of the "Marvel's Agent Carter" season 1 episode 8 storyline picks up where the last episode left, as the SSR agent ended up cleared of all charges following the discovery that Dr. Ivchenko (Ralph Brown) had hypnotized chief Dooley (Shea Whigham) to attain one of the Howard Stark items in the SSR vault, then escaping with Dottie (Kyle Bornheimer), though not before making Dooley put on a vest that ultimately explodes and kills him.

Super Hero Hype reports that in the "Marvel's Agent Carter" season 1 episode 8 finale, audiences will finally see Leviathan, the terrorist group that has been linked to the entire season.

The episode's name is "Valediction," and it has been described as follows: "Peggy faces the full fury of Leviathan, as Howard Stark makes his return in the explosive season finale."

Of course, the "Marvel's Agent Carter" season 1 episode 8 will also feature the return of Chad Michael Murray and Enver Gjokaj as the SSR agents that worked with Peggy underestimating her abilities and making her pour coffee for them for months on end, as BamSpacPow reports.

Before tonight's "Marvel's Agent Carter" season 1 episode 8, enjoy these preview clips!