As U.S. forces battle violent extremism around the globe, no setting has been more vexing over the last decade and a half than Afghanistan. Now, as Chain of Command chronicles, Marines have returned to the country to advise and assist the Afghan army, which has been struggling badly in fighting with the Taliban. As the Marines work to better the fortunes of their allies, an officer burns the midnight oil to watch on Skype as his son is born back home.