Nate was given a Plume Fossil by a researcher in Twist Mountain after working to protect it from Kai. He was told that there was a laboratory in Lentimas Town that could revive it.
Upon arriving at the Fossil Research Lab in Take to the Sky!, the scientists there revived Nate's Plume Fossil, turning it into an Archen.
Archen then went on a brief rampage, as he was unfamiliar with his surroundings, but was eventually calmed by Nate. Nate soon learned of Archen's desire to fly and tried to teach it how, but to no avail. Archen then asked to join Nate's team, having grown to trust the Trainer. Nate accepted and caught Archen in a Poké Ball.
Archen is a Pokémon that is easily panicked, as seen when he was first revived from the Plume Fossil. Having woken up in an entirely new environment caused Archen to attack the group in its panic. His panicky nature was also seen when he freaked out upon meeting Braviary. Despite this, Archen can be calmed down by Nate, showing that he has a strong connection with him.
Archen's greatest desire is to fly, but is unable to in his current form, despite many lessons from Nate and Braviary. His failure to fly often causes Archen to cry in frustration.