The Discovery prepares to arrive at the Starfleet and Federation headquarters. Burnham confides that she would like to look for her mother.
The crew is overwhelmed by the headquarters' technology and structure. Starfleet scans the ship, takes control of its navigation, and requests Saru, Burnham, and Tal beam over.
They are met by Admiral Vance and Lt. Willa. Saru learns that the Kelpians joined the Federation. Adira delivers a message from Senna to Vance, confirming the connection to the symbiont and its memories. Adira is taken to the medical bay for a full diagnostic.
A report comes to admiral about Kili refugees who are infected with something undiagnosible. Burnham's offer of help is rebuffed.
Saru and Burnham debrief their journey with Vance while the holo-doctor examines and scans them.
Vance shares that the Federation now consists of 38 member worlds that they are able to make contact with. He refuses to share information on the Burn. He cannot verify Discovery's story so he is unable to accept it until it can be proven.
Because of the Temporal Accords of the 30th Century, Discovery's presence as a time-traveling ship, is considered a crime.
He informs them that until he can be sure of their motives, Discovery will be requisitoned for analysis and retrofit and the crew will be reassigned.
In private, Burnham and Saru debate their path.
The crew is questioned by Starfleet.
Saru and Burnham request the Kili roster of planets visited and are blocked by Lt. Willa. Burnham makes an impassioned plea to let them help.
Georgiou is interrogated by AI who she causes to glitch out. The interrogation is taken over by a human with an especial intereat in Terrans.
The Kili infection is tracked back to mutated plant matter from the planet Urna. As they need an unmutated sample of the matter to make an antidote, Burnham asks if the USS Ticov is still a seed vault ship in Starfleet. Vance wants his people to crew Discovery and Burnham argues that he's wasting time. He takes exception to her tone. Saru smooths things over by offering to remain with the Admiral while Burnham leads the mission, overseen by Willa and her team.
When they arrive at the coordinates, the Ticov is inside an ion storm and they need to pull it out. Detmer shows anxiety as the ship takes ion blasts but they manage to bring the ship out.
Records show the current caretakers of the Ticov are a family of Barzan, Nhan's species, who joined the Federation in the 25th century.
When they beam aboard, the ship is overrun with plant life. No sign of the caretakers.
Georgiou and the man talk. His badge projects his display screen. He hands it to Georgiou who smashes it for its internal chip.
He informs her that no one knows who is responsible for the Burn and that her Terran empire fell centuries ago. He deduces that she joined Discovery because she cares for someone on board.
On the Ticov, the team find a holomovie of the family and the tune being hummed is the song Tal played on the cello. Nhan confides in Culber that she regrets not visiting home before leaving the past.
Nhan finds log entries that indicate the family was killed and the father, Dr. Attis, was desperate to find a cure. They find the family in stasis.
The vault is locked to the caretaker's voice. Burnham is unable to access the seeds and then Dr. Attis appears and attacks her.
Stamets, Reno, and Tilly are working under the surveillance of Willa when Michael contacts them about Attis' situation. They diagnose and confirm a CME (Coronal Mass Ejection) that killed his family six weeks ago and triggered his phasing. They cut power to the stasis chambers to lure him out and transport him into the vault, fixing his phasing in the process.
Addis' grief immobilizes him. Burnham gets through to him and he opens the vault for them.
Dr. Attis refuses to be beamed to Discovery for medical treatment. Nhan decides to stay with the Ticov.
Vance debriefs the successful mission with Saru and Burnham. When Saru indicates Discovery's eagerness for more missions, Vance points out that exploration is no longer a priority for the Federation. Saru draws a comparison with Giotto's effect on art and perspective with Discovery's perspective and what they bring to the current Federation.
Vance relents on his plan to reassign Discovery's crew and also admits that there is no clear theory as to what caused The Burn.
Burnham asks Willa about the music and she says half the people at headquarters know a version of it.
Burnham finds Georgiou spaced out in a corridor. She's non-responsive for a long period and then blows off Burnham's concern when she recovers.
Burnham and Saru confer and Saru warns her that her choice of words needs to be more cautious.