Tensions Running High
Here's the deal: no one in Legend is ever relaxed, and no one ever just kicks up their feet and takes a vacation. For June and Day everything is pretty much a life-or-death matter, so they're always on the lookout or running from something.
Even before Day runs into all the trouble with June, he's in a difficult state—he's running away from the government, scavenging for food, and trying to make sure his family stays healthy. There's a scene that's especially high-octane where Thomas confronts June and tells him that she's under interrogation. You can almost smell the anxiety in the air:
My first instinct is to attack Thomas. That's what I would have done if he'd caught me without so many soldiers around. Lunge at him with everything I've got, knock him unconscious, then reach Day and make a run for the exits. (2.16.1)
Because of all the stressors that these characters are facing, the tone is never easygoing. It's always got a heightened feel to it because the characters are always on their guards. And the actual plotline doesn't help with the tension either—it's filled with potentially lethal twists and turns.