Osyraa has the Viridian chasing Discovery to convince the Federation to let them into the HQ.
Vance holds off on lowering shields, feeling that something's off.
Osyraa checks in on the conversion of Discovery's systems and is told one system has not been converted, some ancient Earth entertainment.
Discovery's bridge crew realizes the Viridian attack is a big show but their guards are aggressive. Zareh arrives, bringing Ryn with him.
Vance prepares to let Discovery in, under secure measures, when Book's ship is detected, arriving through a subspace corridor. Burnham is unable to hail the Federation so Book lands his ship inside Discovery's shuttle bay just as it enters Federation HQ.
Osyraa sends Zareh to investigate the ship in the shuttle bay and goes to see her Science Specialist, Invigilator Orelio, who is overseeing Stamets and the spore drive. She leaves him with a favorite opera playing.
Book equips Burnham with a life sign shielder and sends her to rescue Stamets.
In HQ, Vance figures out that Osyraa is on board Discovery. He orders all ships to target Discovery with weapons.
Zareh brings Book to the holding space with the rest of the bridge crew and Ryn.
Burnham takes on a regulator but gets stabbed in the leg.
Osyraa hails Vance and wants to talk.
In an access tube, Burnham sends a mayday message to her mother.
Vance and his team meet Osyraa's party in the HQ.
In holding, the bridge crew start a tapping exercise that irritates and distracts the guards. They manage to disarm and neutralize the guards.
Ryn attempts to hack into the ship's systems. Book gets them up to speed on Burnham and the away team in the nebula.
Vance and Osyraa begin their negotiations with a holo medic there to act as a biometric lie-detector. Osyraa proposes an alliance between the Federation and the Emerald Chain.
Zareh's regulators find the man Burnham took down and identify the badge she stole. Using that, Zareh locates Burnham.
Orelio removes the neural locks on Stamets so that he can question him.
With regulators closing in, Burnham triggers a venting protocol that sucks the regulator (and Burnham's shoes) into space.
Vance pushes Osyraa to negotiate in clear terms. She wants the Emerald Chain's business legitimized, stating she's submitted a proposal already to her congress to outlaw slavery. Vance also wants the Chain to back away from the pre-warp planets they have been exploiting. Willa and a regulator enter and inform Vance and Osyraa of the regulator's death.
Osyraa presents an armistice document. Vance sits down to read it.
Ryn masks the bridge crew's life signs and they form a plan to escape through a maintenance shaft. Book and Ryn stay behind to defend. Tilly leads the bridge crew out.
Stamets tries to get Orelio to see Osyraa clearly. Orelio tells him that he owes everything to Osyraa and Stamets counters with all the evidence of wrongdoing he's seen. Burnham arrives and stuns Orelio. She tells Stamets he needs to get away but he refuses to leave because he needs to take Discovery back to the nebula to rescue Culber and Adira. She performs the Vulcan nerve pinch on him to knock him out
Vance is impressed with the armistice but requires Osyraa name a representative for The Chain, who would be independent of her and who would try her for her crimes. She is unwilling to go so far and leaves the ready room.
Osyraa returns to Discovery in a bad mood and tries to get Orelio to leave the bridge while she deals with Book and Ryn. He chooses to stay and watches as she executes Ryn, despite Book offering to take her to the Verubin dilithium supplies.
Burnham secures Stamets in an escape pod and triggers a hull breach to jettison him into space with a homing beacon for the Federation to retrieve. Zareh finds her right afterward and takes her into custody.
Tilly's team breaks into the armory and arm themselves. They hear a sound and the Dot-23 maintenance drones appear. Tilly realizes that the sphere data hid itself in the drones and now they are willing to help take back the ship.