They never spoke of what happened again. Flack tells Mac it was self-defense, but Mac points out they were too young to know the difference. Mac compares DNA evidence from a cigarette butt of Jimmy's he took when they spoke to the puzzle pieces and the bloody T-shirt and doesn't find a match, thus proving that Andy must be the brother involved. This confuses Mac, since Andy wasn't present when it happened. Stella looks through the evidence again and discovers something odd. The unused Chicago puzzle pieces had blue place markers on them, and the NYC pieces had green markers. When she left a piece of the NYC puzzle at a man named Drew Bedford's work, she went back for it, but she actually had picked up a piece of the Chicago puzzle, which she wouldn't have had yet. Drew (Andrew) is revealed to be Andy, and he has been attempting to woo Stella in an attempt to get closer to Mac. Taylor and Flack race back to the city so they can assist in his capture. During a sweep of his office though, Andy hits Mac over the head and drags him off down a secret tunnel. The CSI team rushes back to the lab where they find that an MP3 player that had been rigged to control a murder scene/subway train earlier, in an attempt to kill them, has a song left on it. The song is called "Train to Nowhere", and is track 6 on an album. This points to the abandoned City Hall # line station. They realize that Andy leaving obvious clues to his whereabouts must be a trap, but with Mac's life on the line they have to try something. Flack says he was expecting this and brought along some insurance.