While Hank tries to bond with Megan, Supergirl and Alex discover that a woman named Roulette is running an underground fight club using aliens as gladiators. Meanwhile, Mon-El convinces Winn to take him out for a night on the town.

Supergirl battles a scientist who has been possessed by an alien parasite, giving the ability to drain the lifeforce from anyone he touches. Meanwhile, Alex comes out to Kara, and the Guardian makes his first public appearance.