In Season 4, Episode 2 of , titled " Big Kahuna " , the central plot involves an undercover sting operation by Federal Agent Dave, who poses as a massive client for Dean’s hot tub business. The "Big Kahuna" Sting

Sara’s kidney donor family, Carl and Jenny, return unexpectedly, announcing they are moving to Detroit.

This episode marks a major shift where the investigation into the girls' counterfeit operations becomes much more personal and dangerous. Good Girls Season 4 Episode 2: 'Big Kahuna' Review

The episode ends with Dean being arrested for money laundering because he handed over the incriminating books to the undercover agents.

The family actually wanted to give Ruby and Stan money—specifically $87—leaving Ruby feeling sheepish about her outburst. Annie’s Struggle

"Dave" (Agent Dave) insists on reviewing the company's financial books before finalizing the deal. Despite Beth's explicit instructions not to, Dean hands over the books at a bar, effectively giving the feds the evidence they need for his arrest. The Hill Family: The Donor Storyline