Lewis and Sheppard investigate the shooting death of a man in his own home. The long-standing rivalry between the victim and his identical twin brother leads them to a reason for the killing. Ballard and Gharty team up with a narcotics detective from Washington, D.C. to check out a teenager's fuzzy account of a D.C. drug buy that led to his friend being shot and killed. Mike surprises Gee with news of his transfer into the BPD as an FBI agent liaison, and Gharty decides to leave his wife.