The Red Angel
Summary
While preparing for Airiam's funeral, her system is purged of the Control virus along with all other Control systems around Starfleet. While doing this, Tilly discovers a bio-neural scan of the Red Angel in Airiam's code that matches Burnham. Leland reveals that Section 31 built the Red Angel time travel suit twenty years ago in a temporal-arms race with the Klingons and that Burnham's biological parents had been part of that program. Leland's carelessness at the time led to their deaths. The crew now plan to use Burnham as bait for the Red Angel. Discovery travels to Essof IV, where there is enough energy to power their trap. Burnham is left out in the planet's unbreathable atmosphere until the Red Angel appears.
Summary from Wikipedia, CC BY-SA 4.0.
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