It's Thanksgiving Day at National City in the upcoming episode 8, titled "Medusa," of the second season of the American superhero series "Supergirl."

On the next episode, a visitor appears in National City. Eliza (guest star Helen Slater) decides to visit the town to celebrate Thanksgiving with her daughter. Because they are all gathered together, Alex (Chyler Leigh) feels that it is the right time to come clean and come out to her mother. Kara (Melissa Benoist), on the other hand, couldn't wrap her head around Eliza's assumption that Mon-El (Chris Wood) has feelings for her.

Meanwhile, Winn (Jeremy Jordan) and James (Mehcad Brooks) have both thought of sharing to Kara about the Guardian. Elsewhere, Cadmus has started unleashing a virus that could cause instant fatality to any kind of alien near it. In order to face off the city's newest problem, Kara asks for the help of an unexpected ally — Lena Luthor (Katie McGrath).

Also, fans should watch out for the superhero crossover. "The Flash's" Barry Allen (guest star Grant Gustin) and Cisco Ramon (guest star Carlos Valdes) have returned to ask for Kara's help in the alien invasion in their Earth.

The sneak preview for the upcoming "Supergirl" season 2 episode, "Medusa," shows Danver's Thanksgiving dinner. It starts with Kara getting most of the attention at the dinner table after her guests express their fondness of her, which is most likely an expression of interest. However, out of nowhere, Kara's sister, Alex, decides to take away her spotlight and drops a bomb about her real self.

Meanwhile, Lillian's Brenda Strong shared on Entertainment Weekly on what Project Medusa is.

Strong explained, "Medusa plays very strongly in the next episode, which is episode 208, and it's basically a virus. It's one of those exclusive viruses that doesn't touch anyone whose organic material is human. It only attacks anything that is alien, and it's a big one. So, that poses imminent threat to the planet."

"Supergirl" season 2 airs Mondays at 8 p.m. on The CW.