Dex goes undercover after she is hired by a local politician to dig up dirt on his political opponent. Meanwhile, Grey and Liz's romance continues, and Dex celebrates a tense Friendsgiving at Bad Alibi.

Dex goes undercover as a high school substitute teacher after an old classmate of hers enlists her help to find out who planted drugs on her daughter. Meanwhile, Dex and Liz's relationship gets too close for comfort.