Frank attempts to stop Cathy from testifying. With Hammerschmidt sniffing out the truth, the Underwoods throw someone close to them under the bus.
In the Executive Residence, Frank tries to convince Cathy to not testify, to no avail. Frank then pushes Cathy down a flight of stairs, and calls for help, claiming she's fallen. Cathy is hospitalized and thus prevented from testifying in front of the Declaration of War committee.
Frank holds a press conference in the oval office regarding the Syrian gas bombings. However, the press ask him about the growing possibility of impeachment.
The next night, Claire and Frank hold a dinner for Doug, where they try to convince him to take the blame for Zoe's murder. Doug is off-put at first. He goes to LeAnn and "confesses" to Zoe's murder, though she doesn't believe him.
Meanwhile, Hammerschmidt is continuing to receive messages via birthday cards from someone within the administration. It is revealed that Doug is in possession of birthday cards that have been used to send to Hammerschmidt.
Claire discovers that Tom has been continuing his manuscript, including the things she confessed to him, such as Zoe and Russo's murder. Frank asks how she could be so careless. Claire goes to visit Tom, who blackmails her. Claire and Tom have sex, where he suddenly dies from poison he ingested at the hands of Claire.
LeAnn and Nathan Green give their testimony. Frank, watching, debates whether he should go down and give his testimony. While he is urged not to, Frank goes to the committee and testifies. Frank admits to doing nothing wrong, but claims to respects the office of the presidency to allow the investigation to go on. As a result, he announces he will resign the following day.