The celebration on Jeremiah's (Dean Cain) return on last week's episode was cut short after it was revealed that the adoptive father of Kara/Supergirl (Melissa Benoist) has actually been working for Project Cadmus, and tonight's episode will feature Kara and Alex (Chyler Leigh) breaking some rules in order to find out and stop what Project Cadmus is up to.

To recall, last week's episode 14 of "Supergirl" season 2, which came with the title "Homecoming," featured Kara rescuing Jeremiah from his supposed captivity in Project Cadmus. After having thought for a long time that their father was dead, Kara and Alex, naturally, celebrated Jeremiah's return.

However, it turned out that the jubilation on Jeremiah's return was premature as it was later on revealed that everything was a part of a bigger plan of Project Cadmus. As Jeremiah was able to steal the data from the alien registry, it was believed that Project Cadmus will be up to no good against the aliens. And, true enough, the kidnapping of the aliens will begin on tonight's episode.

"Cadmus stole the alien registry. They're abducting everyone on the list," Kara is heard saying on the promo for the upcoming episode.

According to the synopsis for tonight's episode, Kara and Alex will both agree to break some rules in order to foil the plot of Project Cadmus. As far as Kara is concerned, she will agree to have an interview with Snapper Carr (guest star Ian Gomez) so that the journalist will be forced to run a story that will help the Girl of Steel stop Project Cadmus.

Meanwhile, based on the promo, it is apparent that Alex and her biological father will come face-to-face again. However, it seems that she will fall on his trap once more as he asks her to help him.

"Cadmus is going to slaughter them. I can stop them, but only with your help," Jeremiah tells Alex in a scene in the promo.

It seems that Jeremiah will succeed in talking Alex into what he wants as Alex eventually engages into some action. However, the scene before the promo ends shows a confused and agitated Alex asking her father, "Are you with me?" which hints that her father may have betrayed her once again. 

Tonight's episode 15 of "Supergirl" comes with an episode title "Exodus" and is slated to air over The CW at 8/7 C.