"Parasite Lost" is the fifth episode of the fourth season of Supergirl, and the seventieth episode overall. It aired on November 11, 2018.


Colonel Haley makes a surprising decision regarding Supergirl. Kara writes a series of articles highlighting aliens in National City in the hopes that humans will stop being so fearful of them. Unfortunately, the article puts some of the aliens in harm’s way.[1]


  • The episode's title is a play on the John Milton epic poem Paradise Lost.
  • The episode was previously titled "Parallax".[2]


  1. "Supergirl - Episode 4.05 - Parasite Lost - Promotional Photos, Promo + Press Release" - SpoilerTV
  2. "Supergirl - Episode 4.05 - 4.07 Titles Revealed" - Spoiler TV