I know it's not over
Baby I'll work this out, for sure
It's gonna be colder
And now you force open the door
I know you better than I ever have before
I know you
I know you're a fighter
But you never fight for me
When I was a shelter
You're not heading home to me
We could be closer, we could be closer
We could be
When it's just us
You show me what it feels like to be lonely
You show me what it feels like to be lost
I take your hand for you to let it go
Let it go, let it go, let it go (x2)
It's gonna be, it's gonna be better
It's gonna be better
it's gonna be better
It's gonna be better
It's gonna be better
It's gonna be better
It's gonna be, it's gonna be better
It's gonna be better
We'll take long walk, down the alleys of these houses
And we'll talk, see what conversation rouses
When we're alone, when we're alone
It could be home
When it's just us
You show me what it feels like to be lonely
You show me what it feels like to be lost
I take your hand for you to let it go
Let it go, let it go, let it go
It's gonna be, it's gonna be better
it's gonna be better
It's gonna be better
It's gonna be better
It's gonna be better
It's gonna be better
It's gonna be, it's gonna be better
It's gonna be better (x2)
It's gonna be better
Well considering halcyon means a period in time that was particularly peaceful and tranquil, I'm thinking that Ellie is saying that that point in the relationship is just starting to bud towards the end of the song. Especially when it is juxtaposed with the loneliness in the beginning of the song.