S11, E17: A drunk college student discovers the dead body of a Secret Service agent just before a presidential visit to the area. Booth is ready to hit the ground running and turns to Secret Service agent and former colleague Brandt Walker for information, but is surprised to learn the Secret Service has reservations about Booth’s involvement in the case. The team uncovers some shocking evidence that heightens the seriousness of the case, causing Booth to step up for his country. Meanwhile, Brennan is out sick with the flu and former intern Dr. Colin Fisher returns to the Jeffersonian to run lead on the case, but Brennan refuses to be kept out of the loop. Also, Hodgins takes his life into his own hands and turns a corner after a potentially dangerous experiment.