'Supergirl' Season 4 Air Date, Spoilers: Sneak Peek at Upcoming Installment's Premiere Episode Reveals Dream Girl and Mercy Graves

The CW recently released promotional photos for “Supergirl” season 4's premiere episode which are chock full of Easter eggs for fans to enjoy. Comicbook recently compiled the photos in a gallery for fan viewing.

Aside from shots of Kara Zor-El (Melissa Benoist), the “Supergirl” season 4 photos include a sneak peek at Kara Zor-El's new mentee, Nia Nal (Nicole Maines). Fans of the comic book may be familiar with the character as Nura Nal, who is also known as Dream Girl. The original Dream Girl was a precognitive alien that eventually joined the Legion of Super-Heroes.

Fans also get a sneak peek at “Supergirl” season 4's latest threat to Kara Zor-El and friends. Rhona Mitra's Mercy Graves is shown with her brother, Otis (Robert Baker), in what appears to be the CatCo offices, potentially being a direct threat to Supergirl and Nia Nal. According to Comicbook, Graves will become the face of the “human first” movement, which means that fans can expect her to return after the “Supergirl” season 4's premiere episode.

Nia and Mercy Graves's entry into the series is not the only thing that fans can be excited about in “Supergirl” season 4. The season 3 finale ended with a surprising reveal of a Kara Zor-El clone somewhere in Siberia.

Unfortunately, while fans may be excited by “Supergirl” season 4 adapting the classic comic book “Superman: Red Son,” it seems fans will have to wait for the installment to progress before the Kara clone story is touched upon. In addition, fans of the comic book may have to accept that “Supergirl” season 4's adaptation of “Red Son” will be significantly different and may simply take cues from the Mark Millar classic.

Fans of Kara Zor-El can look forward to her new adventures when “Supergirl” season 4 airs for regular broadcasting with its season premiere on Oct. 14.