Kara is moved by the story of a missing woman named Izzy and decides to investigate despite Snapper Carrs order to leave it alone. Kara takes Mon-El with her to the last place Izzy was seen and the duo find themselves thrust through a portal to another planet, Slavers Moon, where the downtrodden are sold as slaves. The leader of the trafficking ring is none other than Roulette. To make matters worse, Slavers Moon has a red sun, which means Kara and Mon-El are stripped of their powers and stuck on the planet with no way home. Meanwhile, back on Earth, Alex blames herself for Karas disappearance, fearing shes become too focused on her new relationship with Maggie and too complacent in watching out for her sister.