Numb3rs Episode 4.14 Checkmate

Don's old flame Robin Brooks returns to California to prosecute incarcerated criminal kingpin Jarobi "J-Light" Taylor. Don and his team get involved in the case when three key witnesses are murdered, and it's discovered that Robin is the next victim. With all of the "lucky breaks" J-Light is getting, everyone is sure he's still running his operation from jail, but no one can figure out how. The only person to visit J-Light regularly is a troubled teen and chess prodigy, who goes by the name Bishop. However, Bishop is insistent that J-Light is simply teaching him chess lessons during their meetings, and dislikes how the FBI is trying to take down the only person who has ever cared about him. However, once Charlie, Amita and Larry get a hold of Bishop's chess notes, they discover that J-Light's orders are secretly encoded in them. Don and his team must keep Robin safe while they tie the recent murders back to J-Light and his gang.