Uncharted 4: A Thief's End is more than just the final adventure for Nathan Drake. It is also a lesson to anyone who feels like their glory days are slipping away. The game follows Nate sometime after Uncharted 3: Drake's Deception and shows how he lives a semi-normal life as an underwater salvager. While exciting by any normal person's standards, the nine-to-five life as a diver never sits well with Nate. In fact, he often stays in his attic with the relics of his past adventures and relives the good old days shooting targets with a dart gun.
Eventually, his longing for the past wanders into his home life with his wife, Elena, creating a rift in their marriage. As Nate hits a point where he has to make a life-changing decision, his long-lost brother, Sam, comes back and offers him one last adventure. As Nate looks at Sam, he is reminded of his past and the harrowing life he led and agrees to one more journey into the unknown. However, it becomes clear that Sam is more than a promise of excitement; he's also a life lesson in the making.
While searching for Henry Avery's lost pirate city of Libertalia, Nate encounters more danger than anticipated. Even his mentor and closest friend, Sully, tells him that this journey may not be worth it. But Nate quickly dismisses his friend's concern as this lost treasure is important to him. More than reliving the glory days, Nate is reminded of the times when he and his brother used to look for Libertalia together. He believed that finding it would finally close a chapter in his life between him and his brother that was never properly ended.
Eventually, his treasure hunt takes a turn for the worse. Sam betrays Nate, nearly getting him and Elena, who tracked Nate down to ensure his safety, killed. As he processes what happened between him and Sam, Nate realizes that the best adventure he ever had was standing beside him in Elena. Eventually the two reconcile, and Nate is reborn as a man with a newfound purpose to protect those closest to him rather than chasing endless adventures as his brother had. To Nate, Sam was nothing more than a representation of a false dream about a life he felt he was missing.
Nate and Sam eventually find the treasure within the city that they had spent so long hunting for. But it nearly came at a cost. For Sam, this discovery was all he had, and even he was going through his own catharsis as he realized he wasn't alone anymore. Rather than die with his dreams, Sam goes with his brother. However, rather than settling down, Sam instead decides to join Sully on another harrowing escapade, but now knows better than to uproot Nate, who sees his brother as more than family, but also as a reminder of a possible future.
Before he rediscovered Nate, Sam lived his life by surviving. He spent years on the run paying off debts and barely escaping with his life. While it sounds like excitement on the surface, it's no way to live. Sam never stops adventuring, but he does learn that there's more to life than surviving, there's family to consider. By contrast, Nate sees his brother as a lesson that all good things must come to an end before they wear out their welcome. In Nate's case, this means no more deadly adventures involving life-threatening traps and shootouts. If Nate ever feels an itch for adventure, he only has to look at his family and remember the lesson that he learned from Sam.