Is Magical Girl Lyrical Nanoha StrikerS set in a different world/universe
It's the same universe - just some 10 years later.


Nanoha, Fate, and Hayate are all grown up. (teenagers as opposed to kids)
Signum, Vita, Zafira, and Shamal don't age at all because they are bound to the Book of Darkness (they're not human).