The Democrats' House impeachment inquiry against President Donald Trump will close out this week's public hearings Thursday, starting at 9 a.m. ET. You can watch the House Intelligence Committee's live YouTube stream here:

WATCH LIVE: Open Hearing with Dr. Fiona Hill and David Holmes www.youtube.com

Who's testifying?

Thursday's hearings will feature testimony from Fiona Hill, a former Russia adviser at the White House who served until this summer as a top director on the National Security Council, and foreign service officer David Holmes, an American diplomat who serves as the counselor for political affairs at the U.S. Embassy in Kyiv, Ukraine.

What's the background?

Yesterday's hearing featuring U.S. Ambassador to the European Union Gordon Sondland was the most dramatic to date, with Sondland claiming there was a quid pro quo for Ukraine to publicly announce investigations into Burisma and 2016 election meddling in order to secure a White House call and a meeting between President Trump and Ukraine President Zelensky.

It appears that the drama will continue in Thursday's hearings.

It was reported Thursday morning by several outlets with access to Hill's prepared opening remarks that she plans to go after Republican lawmakers on Thursday for pushing what she calls a "fictional narrative" about Ukrainian meddling in the 2016 presidential election.

Hill will gives House investigators a window into former national security adviser John Bolton's objections to Trump's Ukraine activities, Axios reports in a morning briefing ahead of the hearing.

Last month in her closed-door testimony, Hill said Bolton warned about a "drug deal" being cooked up by Trump's deputies, including Rudy Giuliani. She also said that Bolton called Giuliani a "hand grenade that is going to blow everybody up."

Holmes attended a lunch in July in Ukraine with the Ambassador Gordon Sondland, in which he overheard a phone call Sondland had with Trump about investigations into Ukraine. After the phone call, Holmes claimed in his closed-door testimony that Sondland recalled that Trump only cared about the "big stuff" that affected him, in reference to the Biden investigation.

Lawmakers hope by questioning Homles they will be able to suss out more details about that phone call, and consequently, Trump's state of mind surrounding the events.