Horatio goes head to head with Ron Saris, now a criminal informant, when the person, Jimmy Castigan, at who's house he's staying, falls into the pool and is boiled to death by a highly toxic acid. Ron insists he had nothing to do with it and even claims he's the one who was probably targeted, most likely by Julia Winston, who blames him for scarring her face. Horatio looks into the truth of what Ron says about Julia and discovers she's gone off her meds. The CSIs investigate and the evidence leads them to them back to Ron Saris when they find cigar remnants that Saris had at a scene with two dead bodies decomposing in plastic barrels. He claims the cigars were Jimmy's and admits that Jimmy was bragging about a murder with a partner, Sean Echols. Ron actually leads them to the right direction and they find a third body at Sean's house. They link all of the bodies to missing people a woman says are her husband, brother-in-law and sister-in-law. Jimmy was bragging too much about shooting the three of them when they mug their car. Sean shut him up the same way they disposed of the bodies. Ryan finally turns Tara in for her oxycotin addiction and Hoatio encourages Julia to stay off her meds this time so she be deemed incompetent to stand trial for pulling a gun on the crime lab.