Brother's Keeper is the twenty-first chapter in Uncharted 4: A Thief's End.
After parting ways with Elena and Sully, Nate embarks on a journey to find Sam, who is determined to find Avery's treasure. Nate scales the mountain and traverses the inner caverns until he makes his way down to a lake where Avery's ship is.
While hidden, he eavesdrops on a conversation between Nadine and Knot. They have finished loading up a dinghy with some of the treasure when they notice Sam speeding off towards the ship in another dinghy that he had stolen. A frustrated Rafe, accompanied by Orca, storms up to the deck, prepared to set off to the ship using the other boat. Nadine, however, is indifferent and states that they are done. This bewilders Rafe, as their end goal is right in front of them. Nadine refuses to board on the ship due to all the traps Avery had set, along with the fact that most of Shoreline has died or deserted. Her decision to settle for the small haul irritates Rafe, which he tries to claim is the reason her men have left her. Still uninterested in the full reward, Nadine states that Sam can have the treasure if he can survive the ship's traps, and that he would be much more deserving of it than Rafe. He retaliates by slapping her across the face and continuing to demand that she join him, but is suddenly knocked to the ground by her and held at gunpoint. Before Nadine can make any further moves, she notices that the two lieutenants have their rifles trained on her and is forced to surrender. As he gets back up, Rafe reveals that he bought the mercenaries off so they would be loyal to him first.
With no other choice, Nadine boards the dinghy and the group sets off for Avery's ship, with Nate following soon after.