Warning: SPOILERS ahead for Westworld's season 2 premiere
Westworld season 1 was more concerned with its robot characters than its humans, but there was an important subplot involving a conspiracy to sneak information out of the park using Dolores' father, Peter Abernathy. When Theresa Cullen's efforts to broadcast data out of the park using a woodchopper host failed, her co-conspirator Charlotte Hale drew disgruntled writer Lee Sizemore into her web and the two of them put the code inside the brain of Abernathy, who had been decommissioned and was in cold storage. This subplot comes back into play in the season 2 premiere.
To recap, the park's late co-founder Robert Ford was extremely protective of his intellectual property - the code that makes the hosts function. Because of this, he made sure it was extremely difficult to transmit any information outside of the park, and all of the hosts' data was stored locally. Charlotte, the executive director of the board of Delos Incorporated, wanted to get her hands on the code to ensure that Ford wouldn't wipe it from the hosts' memories when he was forced to retire - thereby robbing Delos of the chance to use it in other pursuits.
Related: Why Is There A Tiger In Westworld?
In the wake of Westworld's hosts massacring the park's guests and security forces, Bernard and Charlotte regroup with the other surviving Delos higher-ups. However, when the others fall for a trap, Bernard and Charlotte escape and reach a secret underground room that Charlotte has hidden in the park. This room is populated by drone hosts - creepy white robots who are at work removing brain modules from the park's regular hosts. From this room, Charlotte is able to contact Delos and request help, but Delos says that they will not send in a rescue team until Charlotte delivers Abernathy.
Fortunately, Charlotte has Westworld's Head of Programming on her side (though she doesn't yet know that he is a host as well). Bernard uses the host mesh network to search the park for Abernathy, and presumably their search is successful, since the scenes that take place two weeks later show Delos sending in the cavalry via boat (it's revealed in this episode that all of the parks are on an island).
Abernathy had a small but vital role in the first season of Westworld, memorably appearing in a scene where he recites ominous dialogue from Shakespeare plays (a relic of his time spent in the role of a cannibalistic cult leader called The Professor), during his final interview with Ford. When he was decommissioned and lobotomized, his brain was emptied of his personality and memories, which created enough space to store the data that Charlotte wanted to sneak out of the part. It's likely that Delos wants to use this information as part of their secret agenda, which was hinted at repeatedly throughout season 1, and will almost certainly come into play again in season 2.
Westworld airs Sundays at 9pm on HBO.