A note to any high level flying in to do this (and Just Ask Alice): You actually have to enter the water wheel complex on foot (or mounted, but not flying). Simply flying to the platform with Gerenzo won't activate this quest.
Eccentrica 2011-02-28 (Обновление 4.0.6)
Confirmed. You can fly to the top of the hill, and dismount. Once you set foot on the wooden bridge leading down to the water wheel the quest will pop up.
framdwarf 2012-03-28 (Обновление 4.3.3)
I landed at the top of the mountain in order to dismount & get quest but I was given the quest while mounted, looks like you just have to be at the top of the bridge.
woofwolf 2012-05-15 (Обновление 4.3.4)
Mounted or on foot at top of hill before the wooden ramp will give the quest. Thank you for the suggestion. Loremaster for ever ...
fordahord 2012-12-20 (Обновление 5.1.0)
Thanks very much -- I was going crazy trying to find this quest. After I got the quest on the pathway, I was able to fly in to make the kill.