“Make It Reign” is episode twenty-two of season three of Supergirl.
At the end of the previous episode, “Not Kansas”, Selena and the other two Sisters arrived on Earth to be greeted by Colville and made a Fortress. They try to summon Reign, but the Harun-El is toxic to them. However, Colville can help.
On Argo, they enter Selena’s house and find instructions on how to make Worldkillers. The Daughters of Juru made three and sent them to Earth. Now, they need to contact the DEO.
Ruby thinks Sam is sick. Sam agrees. She doesn’t know what is wrong, but is going to call Lena and Alex to find out.
M’yrnn and J’onn find Alex at the DEO. M’yrnn has come to say goodbye. He reassures her he will live on in J’onn’s memories. J’onn leaves Alex in charge.
In Selena’s house, they find the scabbard of the Sword of Juro, but no sword. And a hologram crystal. Selena’s hologram has a whine at them and explains that the Worldkillers were supposed to rise long ago, but the human side was too strong. Reign and Sam needed to be separated; that’s why Kara was given the Harun-El. Only one will survive the split and Reign will wipe out humanity with seismic events and transform Earth. Then the hologram triggers a bomb.
Alex and Lena are examining Sam. Lena says Sam’s blood cells are transforming into Kryptonian ones. Ruby asks if yellow sunlight will help.
Winn gets Demos to test a new device, a personal shield that is the cornerstone of his non-lethal technology. It seems to work.
J’onn and M’yrnn are getting ready to do the ceremony. M’yrnn explains what will happen and the memories J’onn will gain.
On Argo, Kara says Selena couldn’t have known Kara would return. She must have had another option. It turns out Kara’s father was working on a transmat portal, but never finished it. It could be that Selena did. It’s in Kara’s father’s lab.
The ceremony is done to bring Reign forth. However, it doesn’t work fully. They need the blood of the other two Worldkillers. Colville knows where samples are.
Which is at the DEO lab. Where the sun lamps aren’t helping Sam. Lena is going to head back to her own lab.
Mon-El is working on the transmat portal. They need a way of contacting Earth. Which is by using the crystals to contact Winn through the hologram of Alura.
Sam is dying and Reign is getting stronger. The Sisters of Juru are heading to the DEO to get the blood they need to heal Reign. And Kara and Mon-El are still stuck on Argo.