Daniel Boone loves the Kentucky frontier. It’s his favorite place to hunt.
It’s also the hunting grounds of the Shawnee people, who warn him not to come back there, or he’ll suffer the consequences.
Daniel Boone does it anyway, and also founds a fortified settlement called (of course) Boonesborough. People move in.
The Shawnee kidnap Daniel Boone’s daughter, Jemima, and in the skirmish that follows, the Shawnee war chief’s son is killed (likely by Daniel Boone). As is their tradition, Boone is taken by the tribe and becomes his adopted son. During his time in captivity with the Shawnee, he comes to see them as family. Even so, he escapes and runs to nearby Boonesborough to warn people that the Shawnee are coming to deal with the place once and for all.
The Shawnee decide not to choose violence this time, however, and instead offer the settlers an opportunity to be absorbed into the tribe, with the land remaining in Shawnee and Cherokee hands.
This is not what happens, because the settlers don’t see the Shawnee (or any natives) as owning the land, and believe the “frontier” is theirs for the taking. Thanks to Boone’s efforts, 200,000 settlers make their way into Kentucky by the end of the 18th century as the westward expansion begins in earnest. The Doctrine of Discovery is now thoroughly engrained in the minds of American settlers.
In fact, founding father Thomas Jefferson is counting on it.