I haven’t read any of the prequels to this story, so I feel a little lost. (Blame it on the Ten Ficly Bounce!)
One technical suggestion: many of your sentences begin with “Herb,” “he,” or “he’d.” As a creative exercise, try beginning sentences with prepositional phrases, adverbs, adjectives, and -ing words. It shakes up the flow and forces you as the writer to be more imaginative. These tricks have helped me improve dramatically.