After what seems like forever, Supergirl returns from the Holiday break with a new episode directed by Arrow-verse fan Kevin Smith that also features his daughter, Harley Quinn Smith as Izzy Williams, a missing teen that sends Kara out on a mission to find her.

Izzy’s mother visits CatCo and Snapper Carr to see if he would write a story about her missing daughter. Kara is also at the meeting and promises to find Izzy but Snapper tells her not to pursue the story.

Maggie helps Kara out with her story by providing Izzy’s missing case file and mentions how there has been a rash of missing people of late that shows no patterns. Kara gives the file to Winn who finds a connection. It seems all of the missing people had some blood work done at the National City Research Clinic.

Kara goes to investigate and Mon-el, taking a break from his new bartending gig at the alien bar, tags along. What the two discover is that all of missing people are being sold as human slave labour to another planet. Kara, now dressed as Supergirl, pursues the alien scientist, who as disguised as an Earth Scientist, who has gone through a portal. Kara wants Mon-el to stay behind and warn the DEO but he follows her through the portal.

Unfortunately, the planet the two have landed on has a red sun so no powers. As the two start to explore the planet, they are captured by Joe, one of the planet’s inhabitants who has learned English. After talking to Joe, Mon-el realizes they are on Slaver’s Moon. Joe tells Kara and Mon-el that Izzy and others have been taking to the Red Fortress awaiting to be sold.

So Kara and Mon-el walk right up to the Red Fortress and surrenders. In their prison cell, the two find all of the missing people, including Izzy. Kara is surprised that one of their captors is Roulette who seems to have found human trafficking quite profitable. And look who is buying everyone: The Dominators.

Back on Earth, Alex begins to worry when she hasn’t heard from Kara and thanks to Winn, they find out she is on Slaver’s Moon. Unfortunately, J’onn can’t help as the atmosphere on the planet is quite toxic to Martians.

Maggie pays Alex a visit to the DEO but Alex, all worried about Kara, breaks things off with Maggie because she let her happiness be ahead of her sister. Earlier, we see the honeymoon phase of Maggie and Alex as the two spent the night together and are all happy in the new relationship phase.

With Alex leading the mission to free Kara and Mon-el, she recruits Winn to help and find a way to open the portal to Slaver’s Moon and then back to Earth. Winn starts to panic and refuses to go. Why is Winn so skittish? At the top of the episode, Winn got beaten up real bad trying to help Guardian stop some jewel thieves and was about to be shot if Guardian didn’t show up. But Alex gives Winn a pep talk and off he goes into the portal.

Meanwhile, back on Slaver’s Moon, Kara takes a stand against the Mandovians (the alien inhabitants of Slaver’s Moon) and comes between them and the prisoners. Kara takes quite a few hits from their weapons but the prisoners and Mon-el revolt and overpower the Mandovians and start to make their escape.

The DEO have arrived on Slaver’s Moon and Alex tells Winn to stay behind and get the portal to open. Winn vows not to be one of Star Trek’s infamous Red Shits (you know the ones that always get killed on away missions). At least Winn is excited to be in outer space.

As the prisoners make their way out of the Red Fortress, Mon-el is at the rear keeping everyone at bay but he gets hits and ready to get killed by one of the Mandovians but a Dominator tells him to spare Mon-el and bows to him. Methinks Mon-el is the Daxamite prince. Another big reason I think this is in a later conversation with Kara, Mon-el says that the Daxamite prince wasn’t worthy of protection. We’ve seen Mon-el be very selfish and be a party animan and with him slowly wanting to be a hero, I believe he is the Daxamite prince.

Back at the portal, Winn is trying to get the portal to remain open when gets attacked by a Mandovian but he manages to get the upper hand and take him down. DEO and Kara all meet up and make it it to the portal that Winn has opened. Before Kara, Alex, Winn and Mon-el can get through Izzy is captured by a Mandovian. Alex sets off a yellow sun bomb that gives Kara her powers and she frees Izzy. Everyone goes through the portal, even Joe, who wants a new life on Earth.

Later, Maggie and Alex reconcile with the former figuring out that Kara is Supergirl because Alex only reacts that way when it has to do with her sister. Also, Winn has gotten his groove back and is eager to go back out in the field with James/Guardian.

Meanwhile, Mon-el visits Kara at her apartment and the whole ordeal of Kara always putting other people first has inspired him to want to become a superhero, costume, name and all. Mon-el wants Kara to train him and she agrees as long as he will listen to her. These two have crazy chemistry together and totally ship them.

Back on Slaver’s Moon, the two aliens that were seeking Mon-el have arrived looking for him. The scientist tells them that Mon-el was here but is now on Earth and the two kill him for his help.

So glad to have Supergirl back after a long hiatus and so happy that the CW has renewed the show for a third season.