Travel to whichever camp you prefer, then make your way to AREA 2, where you should start finding signs of a Pukei-Pukei. Investigate them, then follow them to AREA 3, along the way examining more clues, and perhaps the odd "??? Rathian" track. Eventually you should track down the Pukei-Pukei, which is definitely not your average specimen! At this point you'll be encouraged to flee by The Handler, and if you do you can pick up the optional quest Pukei-Pukei Ambush to hunt down this beast in a proper quest, rather than in an expedition. It's not strictly necessary, however, so if you're feeling feisty, don't fear engaging the beast now.
|Objective: Hunt a Pukei-Pukei|
|Reward Money: 7200z|
|Time Limit: 50 min.|
|Conditions: HR 11 or higher|
|Failure Conditions: Time Expires / Faint 3 Times|
|Other Monsters: Apceros / Kestodon / Nolos / Gajalaka|
While being more aggressive than usual, the Pukei-Pukei's attacks are generally the same. It'll attack more frequently, sometimes even relentlessly, so the same openings you may have come to rely on for the lower-rank Pukei-Pukei may no longer be there, and of course, this high-rank Pukei-Pukei will do considerably more damage. Capture the monster, or kill it and carve it, after which you'll return to Astera automatically.
Back in Astera, the Commander will babble about this new threat, which he hastens to confront by deploying his strongest hunters. Maybe allowing Zorah Magdaros to ravage the New World and wipe the slate clean would have been a good idea, a natural check on the evolutionary excesses of these monsters, which now threaten to become an even greater threat than Zorah Magdaros? Nah... but then you couldn't have killed them for better arms and armor, hence breaking the Monster Hunter gameplay loop!
Note: Completing this assignment will unlock the optional quest Special Arena: HR Pukei-Pukei.
In any event, high-rank looms before you, and there are a number of changes to keep in mind with this new, open-ended stretch of gameplay ahead of you...