Aaron says his father used to beat him relentlessly. He left home, but kept in touch with his mom. She gave him her jewelry for money so that his father wouldn't find out. The guy ran a very strict household. Aaron wished his dad dead many times, but he didn't kill him. His only regret in all this is that he left Greg behind. Curtis realizes why once he sees all the bruises on Greg's body. He promises to help the boy.
Greg has the same kind of rash that was found on his mom. They are both allergic to a substance that's used to treat dents on cars. Greg's friend, Travis, has such a product as well as knife with a blade that matches the one used to kill Mike Lux. Travis had also been a victim of abuse. He did what he had to do save his friend. Travis never meant to hurt Robin. Her death was accidental. Case closed.
Curtis made a promise to Greg that he would try to help him. That's why he reunites him with Aaron, who promises that he will never leave him again. They can be a family now. It's what their mom would have wanted. Kate is impressed at how Curtis handled the case, so she admits to being the prankster who filled his office with inflated surgical gloves. It was just a little reminder to not let this job go to his head.