In the TV series Edit
Beth is portrayed by Kristen Gutoskie.
In the pastEdit
Before Gilead Edit
Beth was a very talented chef in her past life, whose pesto recipe got her a James Beard nomination.
After the takeover Edit
Present, season 1 Edit
In the brothel kitchen, Beth and Nick are trading bottles of alcoholic beverages and additional contraband for other illicit goods, such as prescription drugs and pregnancy tests that are used by the customers or working girls of the brothel. Nick formally comments the trade with "the Eyes thank you for your service". He refuses her advances.
Another night, when Nick and Beth are meeting again in the Jezebel's kitchen, Nick is curious if she "asked around at the bar" that "nobody's planning anything stupid", and Beth replies that the girls in here are not "in the shape for a rebellion". She asks him to "stay here" with her, for "old times' sake", and warns Nick about the dangerous consequences of "poking around, asking questions", or "being sweet" on a handmaid. 
Present, season 3 Edit
In the Lawrence kitchen, June runs into Beth and Cora who are about to harbor the runaway Martha Alison planning to help her escape. A suspicious Commander Lawrence wants to call a Guardian to send her home but June convinces him to "let her have a chance for something better".
Along with June dressed as a Martha, Beth and Alison head into town to drop the latter at a relay point in a mass laundromat. After the successful drop, June learns from Beth that Alison, a former chemistry teacher, is actually not fleeing from Gilead but getting "deeper in" the resistance to "make bombs.”
At the Lawrence home, Alison suddenly shows up with an injured Martha and they hide her in the basement, but the Guardians that shot her are close behind. An incensed Commander Lawrence calls Cora a "liar" as she excuses the noise in the basement by the sighting of a rat. He orders June to fix things. As he makes to let the Guardians in, June realizes that the woman’s blood is on the wall. As Mrs. Lawrence takes over the job of cleaning up, June returns downstairs. The guardians are looking for the fugitives outside the window and in the house, June desperately trying to calm down the injured woman's moaning to stop her from drawing the Guardians’ notice. The Guardians eventually leave, but the woman dies.
Commander Lawrence, enraged, demands that June dispose of the Martha’s body all by herself. It takes her a while, but she digs a grave and puts the woman in it, then says a prayer over her final resting place. As June soaks in the tub later, Beth comes in with some salve for June’s ripped-up hands. She reports that Lawrence has sent Cora away since "he doesn’t like liars”.
Beth and the new Martha, Sienna, are preparing for a big meeting: All of the Commanders come to Lawrence , because he won’t attend meetings. Beth and June whisper about the dwindling flow of information, likely due to recent roundups among Marthas.
Mr. Lawrence comes upon June sitting with the files from the night before, handing him her five selections. Then she walks into the kitchen and announces to Beth that they’ll have five new, hand-picked Marthas for the resistance: an engineer, an IT tech, a journalist, a lawyer, and a thief.
Beth is able to gain information from the rebel network in spite of her obvious relationship to an Eye.
Nick trades on behalf of the Eyes, i.e. the Eyes' administration tolerates drug trafficking (in a certain measure).
Since the Eyes are involved in trafficking here and due to the obviously frank and trustful contact between Nick, Beth and the "bar people", it is unlikely that Nick or Beth have an official order to spy for the Eyes inside Jezebel's, and thus their interest for rebel activities is solely private. This could mean that they're both trusted members of the Mayday network.