'Star Trek: Discovery' Season 1 Episode 12: "Vaulting Ambition" Recap With Spoilers

A transport departs the ISS Shenzhou bringing Burnham and Lorca to the ISS Charon, the Emperor's [...]

A transport departs the ISS Shenzhou bringing Burnham and Lorca to the ISS Charon, the Emperor's ship. Saru managed to decrypt the information on USS Defiant. Most of it is redacted, but there is some data available on how the Defiant got to the mirror universe. Lorca believes more information will be available at the palace, where they are likely headed. Burnham gives Lorca something to numb his nerves when in the agonizer booths. Burnham is worried about facing Georgiou.

On the Discovery, Tilly and Saru discuss Stamets' condition. His readouts are better, but he's in a coma. Tilly believes they just need to let whatever is happening in Stamets' head continue to happen. Saru is concerned that whatever is happening isn't happening fast enough. If Burnham and Lorca can't figure out where the Defiant is, then the spore drive may be their only way home. Saru is summoned to sickbay and leaves Tilly to fix Stamets.

Inside the mycelial network, Stamets converses with his mirror universe self. Mirror Stamets explains who he is and shakes hands with Prime Stamets. They're transported to a recreation of the USS Discovery. Mirror Stamets explains that he ended up here after an experiment went wrong in his universe. His physical body is also in a coma. He's been trying to reach out and contact Prime Stamets, which is why Prime Stamets has been seeing flashes of the mirror universe. Mirror Stamets wants Prime Stamets to navigate them out. Something is corrupted in the network. Mirror Stamets got swept up in it before and was lost for days. They escape to engineering, where Stamets believes he can give them a way out.

On the palace ship, Burnham and Lorca are brought before the Emperor in a great hall. The Emperor offers any of three Kelpian slaves to Burnham. She hesitates and then chooses Saru. Lorca is brought before Georgiou. He remains defiant and refuses to bow. Georgiou strikes him and promises he will live a long life in the agonizer booths.He has taken to the brig. Georgiou says she is glad Burnham did not die chasing Burnham. She promises Burnham everything will be as it was and refers to her as "daughter."

Tyler is speaking Klingons, cursing humans and threatening to kill everyone. The doctors don't know how to treat a Klingon who is inside a human body. Tyler's personality reemerges for a moment and asks Saru to help him. He begins screaming again.

Lorca is placed in an agonizer booth.

Georgiou and Burnham dine on Kelpian for dinner. Georgiou wants to know why Burnham left and why she was so hesitant to attack the rebels. Burnham concocts a story about Lorca having spies onboard the Charon. Georgiou believes Burnham was conspiring with Lorca to overthrow her. Georgiou calls for the guards to bring Burnham to the throne room and for execution.

Stamets and Stamets try to map out a way out of the network. Prime Stamets finds something affecting Mirror Stamets' arm. Its a side effect of being in the network for too long. Stamets catches a glimpse of Dr. Culber and follows him. Mirror Stamets warns that he'll get lost if he doesn't stay focused.

Because Georgiou loves Burnham, she says she will grant her the mercy of a quick death. Burnham tells Georgiou that she's not the Michael Burnham she knows. She offers Prime Georgiou's old Starfleet dog tag, with the Prime quantum signature, as proof. Once she reads the quantum signature, the Emperor kills everyone in the room except Burnham and one attendant. The Emperor knows about the Federation.

Saru visits L'Rell in the brig. He tells L'Rell that Tyler thinks he's a Klingon. Saru asks for her help, but she says there is nothing to help. Saru tells her about the parallel universe and how the war is over there. L'Rell says that the real Ash Tyler was captured at the Battle at the Binary Stars. They harvested Tyler's DNA and grafted onto Voq.

Stamets chases Culber through the halls of the "Discovery." He winds up in their quarters. Culber tells Stamets that he died.

Georgiou can't see any reason to help Burnham and the Discovery get back. Burnham knows Georgiou loves her Burnham. Georgiou believes the ideas the Federation represents dangerous ideas that must be stifled. Georgiou says they can't get back through interphasic space because it drives the crew insane. Georgiou offers a trade: Burnham's freedom for the schematics to the spore drive.

Saru shows L'Rell what Tyler did after breaking free from his restraints. He clawed up his own chest. L'Rell still refuses to help. Saru has Tyler beamed into L'Rell's cell. She says she can undo it, but only by her own hands.

A Terran officer tells Lorca that all of his loyalists were rounded up. He threatens Lorca because his sister died. He threatens to kill one of Lorca's loyal men. Lorca doesn't know who the officer's sister is. The officer kills Lorca's loyalist.

L'Rell begins working on Tyler. He reacts first by speaking Klingon then English. L'Rell lets out a Klingon death cry.

Stamets remembers watching Tyler kill Stamets. Culber remembers Stamets holding him. Stamets asks for things to be the way they were. They have a moment brushing their teeth and talking about his day. Culber tells Stamets that the Mirror Stamets is the one who corrupted the network and that the corruption will spread and destroy everything.

Mirro Stamets wakes up in the Charon sickbay. Stamets wakes up on the Discovery. Stamets immediately goes to his spore forest and finds it already sick.

Burnham plots a rendezvous with the Discovery. Georgiou tells Burnham that mirror Lorca helped raise Burnham and then when she was older they became romantic. Burnham pieces everything together. Georgiou is sensitive to light. Lorca knew so much about the parallel universe. She realizes that her Lorca is actually the Mirror Lorca.