EThe Darkest Hour would be considered a full 'adventure' in game mechanic terms, it has about 5 scenes (off the top of my head). Whereas I would consider that a one-shot/delve/Con game not an adventure. This is probably even more exacerbated because I often use Adv Path type things.
The Darkest Hour has three scenes, that break at (I hope) pretty intuitive places story-wise: whenever the PCs get enough clues to move forward (and decide it's time to act on their clues), they move forward...into the next scene. When the story-arc is complete, the adventure is over.
Yeah I went back and checked, I thought there were more. I was writing off the top of my head from one read through...
And as I said that is not what I would normally consider an adventure. However I have changed my expectations as to what constitutes an adventure for FC