The Young Rebels - Season 1 Episode 13 The Infiltrator
Overview: The Yankee Doodle society takes in three newcomers, unaware that one of them is a spy planted among them by the British in an effort to learn the identity of the rebel leader. After a mission goes awry, it becomes obvious that one of their recruits has tipped off the enemy of their plans. Unfortunately, they don't have time to route out the infiltrator before the next mission.