What did Gallipoli really do for Australian and New Zealand relations; why do we know so little about the reality of that seminal day, and the ensuing months, in our history; what gets remembered and forgotten; whether we should have been there at all and, perhaps most pressing, whether we've learned anything at all?
The result is Anzac Eve, a play about a group of 20-somethings on their Big OE who find themselves at Gallipoli, Turkey the night before dawn commemorations begin. Armstrong uses the characters - two Australian women and two New Zealand men - to explore a raft of contemporary issues.
Those issues include the modern-day trek to Gallipoli by young Aussies and Kiwis on their Big OE. As Armstrong says, is it really about the solemn commemoration of a dark moment in our history or more to do with a boozy party, possible hook-up and getting the selfie to prove you were there?
He describes Phil (Hayden Frost) as the kind of bloke you might meet at a party - "lots of opinions but not a lot of knowledge" - and Ben (Barnaby Olson) as a left-wing, newly-minted history graduate who challenges those beliefs.
The debate is complicated by conservative Maia (Ruby Hansen) and Lizzie (Trae Te Wiki) who add their thoughts about nationalism, immigration and what it's like to have a family member serving in Afghanistan.
"I've tried not to push a particular line because the characters I don't agree with might come up with better arguments than those I do agree with," says Armstrong.
"I hope those who see it will be confronted rather than offended and will ask themselves, 'what do I think?', and really ponder that. Blind obedience to any type of ideology can be a bit dangerous; it's the same with nationalism."
Anzac Eve opened in Wellington the same day that journalists Nicky Hager and Jon Stephenson released their book Hit & Run: The New Zealand SAS in Afghanistan and the meaning of honour. It alleges our SAS soldiers were involved in a raid on an Afghan village where civilians were killed.
"An hour before opening night, the book's launched and I'm back to thinking have we really learned anything in 100 years?"
What: Anzac Eve
Where & when: Herald Theatre, March 31-April 5