Chuck Bartowski learns more about Sarah Walker's past when they run into her old high school nemesis Heather Chandler (Nicole Richie).

When Heather's nerdy husband Mark Ratner (Ben Savage) turns out to be a key player in a new mission, the agents must attend Sarah's high school reunion to prevent the sale of potentially dangerous super-bomber plans – all the action ends with the ultimate cat fight.

Meanwhile, Big Mike leaves town for the weekend and the Buy More's new assistant manager Lester Patel decides to implement a new sales policy.

It was a funny and effective change, and while the hair and makeup people did great work making her look so different, Strahovski also gave it her all by showing a much more shy, closed off version of the girl we know.

It all led up to one hell of a fight between Sarah and Heather at the reunion, which not only was done to the tune of "Smack My Bitch Up", but also eventually had the women mercilessly beating up on each other in the showers, with the water of course blasting down on them.