The team is confronted with the separate murders of attorney Mitchell Hinde and young mechanical engineer Justin VanderHeyden, linked by the same, oddly non-striated bullet type used to kill both. Adam hacks Justin's cell phone to glean that he was supposed to meet with venture capitalist Andy Stein the night before, but Stein maintains that Justin never approached him. Dr. Hawkes analyzes the programming files on Justin's zip drive to discover that he used 3D metal printing to create a gun. The CSI's research shows the prototype wouldn't have been structurally sound enough to fire consistently, leading them to believe the shooter sustained a shrapnel injury. They match the DNA from a metal fragment recovered at the initial crime scene to a recent parole, Andy Lewis. They arrest him and learn that Andy Lewis had impersonated Andy Stein when Justin approached him at the club with his pitch for metal printing. It was a case of mistaken identity that Andy Lewis jumped on. Lewis had Justin show him the prototype and ended up killing him for the gun. Andy Lewis then killed Hinde, his attorney, for sleeping with his wife while Andy was serving time for a previous sentence. Meanwhile, Jo discovers that Sid is the anonymous donor who gifted ten downtrodden individuals whose loved ones he autopsied with a million dollars each after he was diagnosed with cancer.