On next week's episode of "Supergirl," a new villain called Indigo will threaten to cripple National City, unless Kara (Melissa Benoist) can stop her.

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Actress Laura Vandervoort, who previously played Kara Zor-El/Supergirl on "Smallville," guess stars and will be playing Indigo. Indigo is described as. "A living, strong-willed supercomputer that was sentenced to Fort Rozz after turning against the people of Krypton. Now on Earth, Indigo will let nothing stand in her way."

The episode, appropriately titled "Solitude" will also take Kara and Jimmy Olsen (Mehcad Brooks) to Superman's famous "Fortress of Solitude." Will they find Clark Kent there as well?

Check out the trailer for "Solitude" below:

"Kara travels to Superman's Fortress of Solitude in hopes of learning how to defeat Indigo (Laura Vandervoort), a dangerous being who can transport via the Internet and who has a connection to Kara's past. Also, James's relationship with Lucy reaches a crossroads."

"Supergirl" stars Melissa Benoist, Mehcad Brooks, David Harewood, Calista Flockheart and airs Mondays on CBS at 8 p.m.