On the eve of the worldwide launch of Andrea Rojas's VR contact lenses, Kara and William team up on an investigation that exposes a terrorist plot. Kelly and Alex celebrate an anniversary, but Alex's safety is in jeopardy.

Leviathan's leader comes after Lena to get the medallion, and Lena convinces Supergirl to take her to the Fortress to find a weapon capable of stopping him. Kelly makes a confession to Alex, and John reaches out to his brother.