Undercovers Season 1 Episode 6 (Undercovers s01e06) with title “Xerces” aired on Wednesday, October 27th 2010 at 08:00 pm via NBC Network.
Here is summary for Undercovers Season 1 Episode 6 :

After renowned weapons dealer, Xerxes, hides the formula to a dangerous and lethal biological weapon in a painting, Shaw assigns Steven and Samantha the task of traveling to Tuscany to secure the painting and capture Xerxes.