In the new episode of "Supergirl" Season 2, Kara (Melisa Benoist) will be facing an enemy and she will need another set of hands in order to stop her. The episode is also said to be part of the epic crossover of "Supergirl" with "The Flash," and "Legends of Tomorrow."

According to Travelers Today, the official synopsis of "Supergirl" Season 2 Episode 8 reveals that Kara will form an unlikely alliance with Lena Luthor (Katie McGrath). Lena is Lilian's (Brenda Strong) foster daughter.

It was revealed that Lilian was the one behind the organization CADMUS which is a group that is working on eliminating all the aliens on Earth. It was said that Lena will help Kara to stop Lilian in order to eliminate Supergirl.

Econotimes reported that in her interview with Entertainment Weekly, Strong revealed that Lena did not know about her mother's involvement with CADMUS. She teased that in "Supergirl" Season 2 Episode 8, Lena will know more about her mother's secrets and it will have a huge impact on their relationship. Strong also revealed that the group was working on a strong virus that does not affect humans but only aliens.

Aside from that, "Supergirl" Season 2 Episode 8 will also be its Thanksgiving episode. In the synopsis, Eliza (guest star Helen Slater) will come to town to celebrate the holidays with her daughters and Alex (Chyler Leigh) thinks that it is the best time to confess to her mother about her sexuality.

Meanwhile, Kara will also be shocked after Eliza said that Mon-El (Chris Wood) has feelings for her. Will this be the beginning of a relationship between the two?

"Supergirl" Season 2 Episode 8 will also be the beginning of the epic superhero crossover episodes for "The Flash," "Arrow," and "Legends of Tomorrow."  Barry Allen (guest star Grant Gustin) and Cisco Ramon (guest star Carlos Valdes) will appear asking Kara for help in order to fight aliens who are trying to invade the Earth.

"Supergirl" Season 2 Episode 8 titled "Medusa" will air on The CW on Nov. 28.