In Chapter 18, the story begins on Tatooine during Boonta Eve. Peli Motto cheats a Rodian while Mando and Grogu arrive in search of an IG memory circuit replacement. Motto's Jawas are unable to find one, but she offers to sell them her R5-D4 astromech droid, which resembles the defective one from Episode IV: A New Hope. She also offers to replace their fighter's droid socket and provide an oil bath at a discounted price due to the holiday. Mando agrees, and they depart Tatooine later that evening, guided by the Boonta Eve fireworks.
With a new droid on board, Mando and Grogu continue their mission, flying to Mandalore where he shows Grogu his home planet, Concordia, which was also Boba Fett's original home in Star Wars Legends continuity. They navigate through the dense cloud cover and arrive to a green landscape with glassy terrain. Unfortunately, the Empire's fusion bombs have disrupted the planet's magnetic fields, rendering off-world communication impossible.
Mando orders R5 to retrieve an atmospheric sample while he and Grogu monitor the droid's progress. However, when the droid disappears from the scope, Mando sets out to locate it, leaving Grogu behind with the fighter. He tracks the signal to a cave where he is ambushed by three primitive aliens. Despite the odds, he kills all of them and tosses their bodies into the ruins below. Eventually, he finds R5 and returns to the surface where they learn that the atmosphere is safe to breathe.
Mando leads Grogu to a cave where they fall through the devastated Sundari, a city well-known to fans of Star Wars: The Clone Wars. He takes them to the civic center and guides them down a shaft that he believes leads to the Mines of Mandalore, where they search for the Living Waters.
As they explore the ruined underground area, which is full of broken pipes and building debris, Mando finds a Mandalorian helmet but is suddenly attacked and captured by a large crab-like droid, unlike any other droid in the Star Wars universe. Grogu follows the droid deeper into the underworld and watches as it places Mando, who is webbed in a metal lattice, into a machine before a smaller, humanoid droid with an organic appearance and a large eye disarms him.
After the droid departs, Grogu attempts to free Mando. Unfortunately, his use of Force creates too much noise and alerts the returning droid. Mando orders Grogu to flee and seek help from Bo-Katan. Grogu manages to escape in his pod just in time and returns to the fighter, using the ship's maps to direct R5 where to go.
Bo-Katan is alerted by her droid that they have visitors, and she sees Mando's starfighter approaching. Ready to confront him, she meets the fighter on the landing field of her castle, only to find Grogu alone, which calms her anger. She orders her droid to download the information from the astromech.
Bo-Katan, Grogu, and the astromech board her ship (a reference to The Clone Wars for fans) and fly back to Mandalore. As they break through the cloud cover, Bo-Katan sees her home planet for the first time in years. She describes it to Grogu with a nostalgic tone, echoing what Mando said earlier when he and Grogu arrived.
Grogu guides Bo-Katan through the ruins, chatting with her along the way and encouraging her when she becomes fearful. She speaks to Grogu about the Jedi and pauses when she notices something on the cave ceiling attacking and killing the Alamites, a species that once lived outside the Mandalorian cities. She ponders what other creatures may have survived if they had.
In the meantime, the ominous droid connects tubes to Mando's body and triggers a pump that commences to drain his blood. Bo-Katan arrives to confront the droid and engages in a fight, but the droid uses a shock staff to overpower her. Seizing the Darksaber, Bo-Katan manages to defeat the droid and goes to assist Mando. However, the droid's head detaches and merges with the crab droid. Despite Mando's warning, Bo-Katan uses the Darksaber to demolish the larger droid like an expert.
Mando regains consciousness to find Bo-Katan preparing soup for him. They discuss Mandalore, and he expresses gratitude for her rescue. Bo-Katan proposes that he come with her, but he declines, determined to pursue his mission. Nevertheless, she agrees to accompany him to the mines, although she appears patronizing. On the way, she reminisces about her previous life's triumphs.
Upon discovering the Living Waters, Bo-Katan reads a plaque to Mando that reveals this cave is believed to be where Manda'lor the First discovered a mythosaur – which she finds amusing – and Mando proceeds to bathe in it while reciting the Creed. As he descends into the water, he falls into the depths. She rescues him, and on their way back up, she spots a mythosaur. The legends of her people are genuine, and something within Bo-Katan appears to shift.
