NCIS:LA has to investigate the apparent suicide of a Naval Officer named Calvin Lee, who jumped off a freeway overpass. Traffic camera footage makes it clear that he was alone when he jumped, but because Calvin was the XO of a high-tech submarine, Sam and Callen must investigate him to be absolutely sure Calvin didn't compromise anything before he died.
Calvin's parents immigrated to the U.S. from China in order to escape the one-child laws in China. They have an older daughter to whom they no longer speak. Calvin was apparently engaged to a Chinese national, but the marriage was arranged by his parents and Calvin is gay. When they get to Calvin's boyfriend's apartment, they find him murdered, making them suspect it's a case of murder-suicide. However, evidence leads them to a Chinese hit-man, apparently hired by Calvin's fiancee. They also find the device Calvin threw over the bridge before he jumped. Turns out the device is a hard drive cloner devised by the Chinese government, leading them to conclude Calvin was a spy for China. They question his parents further and uncover that though Calvin was born and groomed to be the perfect sleeper agent, he didn't want to betray the U.S. and committed suicide to avoid being forced to.