The story of a missing woman named Izzy moves Kara to investigate, even though Snapper Carr has told her to leave the matter alone. When Kara and Mon-El check out the last place Izzy was seen, they end up thrust through a portal to another planet, where the downtrodden are sold as slaves as part of a trafficking ring run by Roulette. Meanwhile, Alex blames herself---and her new relationship with Maggie---for her sister's disappearance.