I've had time to think, and I've remembered that I can't make my hero too proactive. There must be a time in the middle when he decides things have gone back to normal, even though the reader can pick up evidence that the villain is still active behind the scenes. Why? Because the hero's single-minded focus on his work, in this plot, will be his potential ruin. It has to end up putting him and those he most cares about in danger, because, as he admits at the end, "I just didn't want to know."
Actually, my heroine is the more proactive of the pair. So proactive, in fact, that my latest beta reader accused her of superheroics at the story's point of crisis. No, sorry, that's staying in. Her issue is wanting to be in control and thinking everything is up to her. Yeah, she'd do what I have her do . . . but it worries me that that beta didn't see it that way.
More rethinking, more rewriting!