Culber reviews the Discovery's experiences so far in this future, noting that the crew isn't doing well. He offers Detmer the opportunity to talk about how she's dealing. She claims to be fine.
Adira still has not regained her memories and still does not have access to Tal's memories, nor how she came to be a host for a symbiont. She has a year of memories from when she was found in an escape pod.
Culber recommends taking Adira to Trill to look for help.
Discovery is welcomed by the Trill and the news of the symbiont on board is good news to Commissioner Vass.
Saru speaks to Stamets about working with Tilly to find a replacement navigation method in case Stamets is ever injured or killed. Tilly suggests a dark matter system. Stamets shoots the idea down.
Culber visits Burnham's quarters and comments that her space is now filled with souvenirs. He asks her to accompany Adira down to Trill instead of him.
Adira is unsure about Burnham accompanying her but likes Culber enough to trust his judgment and they head down in a shuttle.
Back on Discovery, Culber reports his findings about the crew's stress levels to Saru. Saru asks how he can help his crew. Culber tells him they need connection.
On the planet, the Trill welcoming committee is upset to discover Adira is a human hosting a symbiont and that the symbiont's memories are not accessible. Vass advocates for forced separation which could kill Adira. Burnham insists they find another way. Guardian Xi reveals that The Burn decimated their population and that the Trills no longer have enough individuals capable of serving as hosts. He suggests taking Adira to the Caves of Mak'ala so the Tal symbiont can communicate.
Leader Pav decrees that there will not be a forced separation but that Adira is an aberration and must leave to preserve Trill ideals.
Vass leads them into a trap and Burnham fights off the guards who attack them, stunning them and Vass. Guardian Xi finds them and offers to lead them to the caves.
On Discovery, Saru is querying the computer for ways to help the crew. When the standard suggestions aren't enough, there is a visible recalibration and the computer's voice and cadence changes. This new computer recommends laughter as a healing strategy and suggests the films of Buster Keaton and Charlie Chaplin. Furthermore, it suggests giving the crew the night off for rest and relaxation and inviting the bridge crew for a shared meal.
Burnham, Adira, and Xi enter the caves. Adira enters the pools in order for the Tal symbiont to communicate.
Saru welcomes the bridge crew to his table and speaks to them about their decision to follow Burnham. They toast that decision. Detmer does not drink.
Adira enters the pool and enters a trance state.
At the table, Tilly and Stamets have a distinct awkwardness that Culber picks up on. Georgiou breaks the tension with a snarky haiku which sparks a haiku competition. When Detmer is called upon, she declines initially. At Owosekun's urging she tries but her poetry is fixated on Stamets' blood, which makes everyone uncomfortable.
Stamets points out he navigated the spore drive to bring the ship back to Earth. Detmer counters that she's the pilot. Tilly interjects that they're being assholes. Stamets leaves, Culber follows. Keyla leaves, others follow. Saru is sad but understands.
In the caves, the monitor shatters, indicating an instability in the levels in the pool. Vass and Pav arrive with guards. Adira starts convulsing and then submerges. Burnham is permitted to enter the pool but can't find Adira. Xi sets Burnham up with neurostabilizers and she goes under to find and rescue Adira.
In the symbiont realm, Burnham finds Adira who is fighting off tendril that keep trying to attach. Burnham thinks the tendrils are trying to help Adira remember. Adira lets the tendrils attach.
Burnham and Adira witness Adira and a boy named Gray who was about to be joined with a symbiont. Burnham talks Adira through memories of Gray. More tendrils attach and Burnham sees Gray playing a cello. When the memory progresses to a gift Adira gives Gray, Adira freaks out and tries to escape. Burnham convinces Adira that if the past isn't accepted, they can never move forward.
The memory of Adira giving Gray a handmade tapestry is interrupted by the ship's crash. Gray is fatally injured but the symbiont is stable and Adira offers to host the symbiont.
In the realm, the tendrils are gone and the former hosts of Tal appear, including Gray. They welcome Adira.
Burnham and Adira emerge from the pool and Adira is able to speak Tal's names, the memories of previous hosts now accessible to her. The Trill now accept Adira as a host and Pav offers to be their mentor. Adira thanks her but feels their path is with Discovery for the moment. Pav accepts this and hints that Trill will be willing to join the new Federation when it has revived.
Saru sits at his table, alone, and Tilly returns. She thanks him and commends him for his leadership in this difficult situation. Stamets also returns and apologizes to Tilly for how he discounted her idea. He offers to discuss the dark matter interface idea.
Detmer seeks out Culber in sick bay and admits that she's not okay. She asks to take him up that talk.
The crew are summoned to the shuttle bay where it's been set up for a movie night, showing Buster Keaton films. Stamets and Detmer reconcile.
Saru shares a theory with Culber that the sphere data is now protecting the crew.
Adira gives Burnham the coordinates where the Federation can be found. Adira picks up the cello and begins playing a lullaby Senna knew. Gray appears and critiques Adira's bow work. They discuss whether Burnham should know about Gray.