Sherlock helps a math genius from his network of ‘Irregulars’ experts after he stumbles upon a body while participating in a math puzzle competition. Joan attempts to extend an olive…

Dembe reflects on his complicated past when he receives a concerning call from an old connection. An ambitious Congressman begins to question the Task Force’s operations.

A spate of coordinated attacks on Red’s lieutenants puts Dembe in imminent danger, prompting him to relive the events that led him to join the FBI two years earlier.

In a retrospective look at key turning points, steps are retraced that lead Elizabeth Keen to align with a powerful enemy.

After weeks of hunting for Dembe, Red and the Task Force finally get a lead on his whereabouts when Aram goes missing. Meanwhile, Dembe takes a calculated risk as Red…