Originally Posted by bored@lazy
So is this series starting from scratch or is it a sequel? If so I may start watching it...
A bit of both. It recalls events from the manga, such as there being three screenshots of things which happened when Nagi recalls Hayate saving her in the past, but you can watch it without knowing anything about Hayate I guess. It doesn't introduce Hayate, Nagi or Maria, it just assumes you already know them.
I guess the best answer is it's not starting from scratch, but it's not a sequel to season 1 or 2 if you know what I mean.