Skirmish on Terra Nova
The skirmish on Terra Nova was a small scale battle fought between a landing party sent by the Enterprise NX-01 and the Novan descendants of the lost colony of Terra Nova.
Background
In 2078, in the first attempt by Humans to establish a deep space colony, the planet of Terra Nova was colonized by Earth. Due to the success of the colony, authorities on Earth decided to send more ships to the planet and expand the Human presence. However this was met with stiff resistance by the original colonists, and a series of heated messages were transmitted back and forth between Earth and Terra Nova until Earth suddenly lost contact with the colony.
The fate of the Terra Nova colony remained a mystery for decades, until the launch of the Enterprise NX-01, the first warp 5 capable Human starship. In 2151, the Enterprise was sent to Terra Nova to discover the fate of the lost colony.
Skirmish
Upon discovering Human Novans (which the Enterprise crew initially believed were aliens) living on Terra Nova, Captain Jonathan Archer and Lieutenant Malcolm Reed followed them into the cave system in which they lived. Under the impression that Humans from Earth were to blame for the deaths of their ancestors, the Novans attacked Archer and Reed, resulting in Reed being shot in the leg and captured by the Novans. (ENT: "Terra Nova")