Ambassador Sarek is leaving Vulcan on a diplomatic mission. He declines to inform the other Vulcan he is traveling with about the nature of their mission.
On the Discovery, Burnham and Tilly are running laps. Burnham is pushing Tilly to achieve a time that will earn her a physical endurance commendation.
Lorca and Tyler are training against Klingons on a holodeck. Lorca grills Tyler about his past and history. Lorca wants to make Tyler his chief of security. Tyler accepts the position.
Sarek wonders why his ship has not dropped out of warp. He realizes their course has been changed. His traveling companion is a fanatic, part of a group who believes humans are inferior and who want to leave the Federation. The Vulcan begins to glow red then explodes.
Burnham orders a nutritious meal for Tilly. Tilly points out sitting in the cafeteria. She notes his attractiveness and says the word is he killed six Klingon soldiers. Tilly and Burnham sit with Tyler. Tyler extends a hand to Burnham. Burnham feels ill. Her vision blurs and she sees Sarek on the ground.
Sarek and Burnhams Katra bond kicks in. Burnham sees a gathering that she attended with both Sarek and her surrogate mother, Sarek's wife, Amanda Grayson. This is just after Burnham was denied enrollment in the Vulcan Expeditionary Group. Amanda argues, but Sarek accepts the decision and considers finding a place for Burnham with Starfleet. Burnham just wants to go home.
The Sarek from the memory sees the Burnham brought from the present day. He questions what she's doing there, in his mind. He then steps up to her forces her out of the memory.
Burnham remembers learning about her Katra bond.
She wakes in sickbay with Dr. Culver, Captain Lorca, and Cadet Tilly standing over her. She tells them that Sarek is the one in trouble and when they wonder how she knows that she tells them about her Katra bond with her surrogate father.
She also remembers that Sarek believed Burnham could show the heights of human potential. Other fanatics on Vulcan disagreed and tried to have Burnham killed. It was at this moment that Sarek grafted his Katra to hers, not during the Klingon attack that killed Burnham's parents.
Lorca continues a Vulcan Starfleet admiral. He confirms to Lorca that Sarek is hurt and also informs him that the Vulcans tried to go behind Starfleet's back in dealing with a diplomatic problem, which is the mission that Sarek was sent to.
A nebula is making it difficult to search for Sarek. Burnham goes to Stamets, who believes he can use a neural enhancer to boost Burnham's Katra bond and wake up Sarek, but they'll have to take a shuttle inside the nebula. Tilly will go with her to operate the neural enhancer. Lorca assigns Tyler as the pilot and tells him to bring Burnham back without a scratch or don't come back at all.
After they depart, Lorca gets a transmission from Admiral Cornwall. Lorca tries to ignore it, but it turns out the Admiral's cruiser just dropped out of warp and she is requesting permission to dock. Cornwall scolds Lorca for launching an unauthorized rescue mission and many other unilateral decisions. In the end, she says she came to talk to her friend and Lorca pulls out some alcohol.
Burnham tells Tilly that Sarek's dying thoughts are reflecting on how Burnham was his biggest failure for failing to make it into the Vulcan Expeditionary Group. The ship gets a signal and Tilly turns on the enhancer with Burnham attached.
Burnham returns to the memory from earlier. She remembers Amanda giving her the Lewis Carroll book she still keeps with her to this day and how her surrogate mother reminded Burnham to always remember that she is human, all just before Sarek brought news of Burnham's rejection from the Vulcan Expeditionary Group.
Burnham announces herself and Sarek fights her again, though this time Burnham fights back. However, when her readings show trouble Tyler orders Tilly to pull Burnham out.
Meanwhile, Lorca and Cornwall reminisce about old times. Cornwall says she's worried about Lorca and how he's putting the Discovery and its crew into harm's way. She's worried that he's changed since his previous ship was destroyed. Lorca manages to use his charm to change the subject and make the mood more intimate.
Tyler, Tilly, and Burnham try to figure out what they can do. Tyler suggests that Sarek isn't looking at Burnham's failure, but his own. Burnham goes back in.
Burnham returns to the memory. Sarek reveals that the Vulcan Expeditionary Group was willing to accept Burnham, but that they couldn't have a full-human and a half-Human, Spock, both join the rank. They made Sarek chose one or the other and he chose Spock, only for Spock to choose Starfleet instead. Sarek admits the failure was his and that he is ashamed.
Burnham tells Sarek to show her how to save him like he saved her. They mind-meld and Sarek wakes on his ship. He reaches up and turns on his ship's transponder.
Cornwall looks over at Lorca's scars. This wakes him and he quickly rolls over and puts a phaser to her head. Cornwall is angry with Lorca and is convinced that Lorca is not mentally fit ot captain the Discovery. Lorca begs her not to take his ship away.
Lorca joins Burnham in discussing Sarek's health and how to accomplish his mission. Lorca decides to ask Cornwall to complete it. Lorca says he didn't mount the rescue mission for Sarek but for her and then awards her the position of science specialist on the bridge of the Discovery.
Burnham speaks with Sarek. She wants Sarek to talk to him. When he resists, Burnham tells him she won't push him but that they will have this conversation one day.
Before leaving, Cornwall tells Lorca that when she returns they are going to discuss how Lorca will step down and get help and then maybe return to the captain's chair.
Burnham tells Tilly that she gave her bad advice and that she should find her own way to the captain's chair.
Burnham tells Tyler about how she feels unburdened by this new information she got from Sarek. She's feeling an entire whirlwind of emotions. Tyler tells her that's just being human. Burnham offers her hand to Tyler this time.
On Cancri IV, Cornwall tries to negotiate with the Klingons and the Elders of Cancri IV. The Klingons immediately kill the elders and Starfleet guards. They contact Kol, who welcomes them into his new empire. He had been hoping to capture Sarek, but Cornwall will do.
Saru informs Lorca of Cornwall's capture. Saru is surprised when Lorca tells him to contact Starfleet command and ask for orders.