Captain Burnham and the U.S.S. Discovery race to stop Book and Ruon Tarka from launching a rogue plan that could inadvertently endanger the galaxy.

On Trill, Captain Burnham, Book, and Culber must pass a dangerous test to prove themselves worthy of the next clue. Adira reconnects with Gray and Saru’s first day as ambassador is complicated by his engagement to T'Rina.