Plot

When the U.S.S. Discovery's crucial mission does not go according to plan, Burnham realizes what must ultimately be done. The crew prepares for the battle of a lifetime as Leland's Control ships get closer.

Discovery escapes to rendezvous with the Enterprise. Pike has given the order to evacuate the Discovery. Subspace communication is cut off by Control, so Pike cannot contact Starfleet. Discovery and Enterprise dock with each other in space. Burnham recollects that they have only seen 4 of the 7 signals till now.

The Discovery crew is evacuated onto the other star ship, and they initiate the Discovery's self-destruct sequence, but the Sphere data takes control of Discovery's systems and prevents this from happening. It also defends itself from torpedoes fired by Pike at it from the Enterprise. Burnham has a vision of Enterprise being locked in a ferocious battle with the Section 31 ships and losing it. Leland and his troops board the Enterprise and kill everyone. Burnham exits the vision just prior to Pike giving the command to fire Torpedoes on the Discovery. Burnham says that trying to destroy the Discovery will not work as the Sphere data has taken control of the ship's resources and will try to protect itself.

Burnham proposes that the time crystal be used to take Discovery itself to the future where Control cannot get to it, and plans to wear a copy of her mother's suit to lead the ship there. The original suit was coded to Gabrielle's DNA and so Burnham's MRNA is the closes genetic match. Burnham plans to use a new suit to open a wormhole and Discovery and follow it through. At this point they don't have a return strategy from the future. Pike speculates that another signal will appear to guide the team. Spock concludes that since the signals were not set by Gabrielle, they were set by Burnham to guide their efforts in the past. Pike agrees and resumes command of the Enterprise to keep Control distracted.

A new signal appears, leading Discovery to the planet Xahea which is ruled by Tilly's friend Queen Me Hani Ika Hali Ka Po (Yadira Guevara-Prip). Discovery spore jumps to the planet, with the Enterprise using the warp drive to come 1 hour later, and section 31 ships a further 10 minutes behind the Enterprise.

A brilliant engineer, Po has a devised a method to recrystallize Dilithium, which will negate the need for all ships to continually look for new sources of the mineral to power their warp drives. Po helps Stamets, Tilly, and Reno prepare the suit and time crystal for the journey. She devises a method to charge the time crystal by creating a synthetic supernova, by mixing Dilithium and dark matter. But the charging of the crystal in this way will ultimately lead to its burnout. Meaning Burnham can open a wormhole and get to the future, but she cannot return from it.

Burnham decides to jump to her mother's time-line and near the planet Terralysium. Burnham says she can hide the Discovery on the planet as there is no technology there.

Culber makes his peace with Stamets. Stamets says that he will quit serving on a star ship after this assignment and take a desk job instead to restart his life. Some of the Discovery's crew choose to stay with Burnham, as does Georgiou, while Pike makes Saru acting captain. Tyler says his goodbyes to Burnham. Saru sends a farewell message to Siranna.

As the Section 31 fleet arrives, Discovery and Enterprise prepare for battle while the suit and time crystal are finalized.