Michael Cohen plans to give America a peek into Trump Tower, and it's 'chilling,' says lawyer Lanny Davis shared new details about the topics Cohen plans to cover.

When Michael Cohen appears before Congress in coming weeks, he plans to describe details of life inside the Trump Organization boardroom that he witnessed firsthand for nearly a decade, his lawyer told ABC News.

"He needs to tell his personal story to the American people," Lanny Davis, Cohen's attorney, said in a wide-ranging interview for the second episode of "The Investigation," a new podcast focused on the probe led by special counsel Robert Mueller.

"And when he does," Davis added, "you're going to hear personal, front-line experiences of memories, and incidents, and conduct, and comments that Donald Trump said over that 10-year time period behind closed doors that, to me when I first heard Michael tell me all this, even as much as I knew about Trump that was negative, was chilling."

Cohen has pledged to appear before closed sessions of the House and Senate intelligence committees and in a public session of the House Oversight and Government Reform Committee before he reports for a federal prison sentence on March 6.

Davis shared for the first time with ABC News details about the topics Cohen plans to cover when he finally appears. Davis said that while Cohen cannot talk about subjects vital to the special counsel investigation, he can describe his life at Trump's side, where he spent years as a lawyer and fixer.

He said the issue Cohen "can speak to better than anyone" is Trump's character.

Davis said that lawmakers will hear "how he speaks in bigoted words in private, which Michael Cohen will tell you."

"He treats people badly," the veteran Washington, D.C., attorney continued. "He has no moral character in defrauding people in his businesses, and going bankrupt, and taking cash out, and putting people out of work. He lacks the moral compass that we expect in our presidents."

Cohen pleaded guilty in August to six felonies associated with his personal business dealings, including tax evasion and making false statements to a bank, and two felony campaign finance violations in connection with his role in arranging non-disclosure agreements during Trump's campaign with two women who had claimed past affairs with the president.

In November, he pleaded guilty to lying to Congress about a Moscow real estate project that Trump and his company pursued at the same time he was securing the GOP nomination in 2016. Cohen has on repeated occasions scheduled, and then canceled, appearances before Congress in recent weeks.

The president and his advisers have made no secret about how they plan to rebut claims made by Cohen, repeatedly describing him in media interviews as a dishonest broker who will say anything to try and reduce his impending prison sentence.

"The man is pathetic," Trump lawyer Rudy Giuliani told ABC News Chief Anchor George Stephanopoulos in December on "This Week" Sunday.

"He knows the truth, I know the truth, others know the truth, and here is the truth: The people of the United States of America, people of the world, don't believe what he is saying," Giuliani continued. "The man doesn't tell the truth."

John Dowd, who once led Trump's legal team, told "The Investigation" last week he thought Cohen "has done a great job of putting the rope around his neck."

Davis compared such comments from the president and his team to mafia tactics. He took issue with a tweet from Trump describing Cohen as a "rat," a euphemism for "snitch" that Davis said could put his client in danger when he reports to prison.

"Here's the President of the United States, the top official in law enforcement and everything else in the United States, using Twitter to call a person who is cooperating with prosecutors a 'rat,'" Davis said. "That in and of itself is an abuse of power that could lead to his ouster."

Davis offered few clues about where he thought the special counsel investigation was headed, other than that he thought it held the potential to do damage to Trump. He dismissed the suggestion from Dowd that the investigation would not yield a report at all -- a prediction Dowd made on the previous episode of "The Investigation."

"It sounds like wishful thinking to me," Davis said.

What he knows, Davis said, is that Cohen contributed "70 hours and seven days" of interviews with the Mueller team.

Davis said the team viewed that testimony to be "relevant, important, significant and it went to the core issues of the Mueller investigation. That's what we know."

Whether the public is ready to accept Davis' portrait of Cohen as a changed man -- "transformed" was his word -- remains to be seen. While the special counsel did credit Cohen's cooperation, prosecutors in the Southern District of New York were not as swayed.

"Any suggestion by Cohen that his meetings with law enforcement reflect a selfless and unprompted about-face are overstated," the prosecutors wrote in their sentencing recommendation. "Had Cohen actually cooperated, it could have been fruitful."

Davis has deep experience in the trenches of political scandal, combining his legal background with his expertise in public relations. He served as special counsel to President Bill Clinton, guiding him through a series of fractious political investigations, including an impeachment trial born out of his affair with White House intern Monica Lewinsky.

Davis, who spent 12 years representing Maryland in the Democratic National Committee, provided a harsh assessment of the Trump tenure, but also expressed some concern that Democrats risked overplaying their attacks on the President.

"We could overreach," Davis said. "And we have a tendency, just like the Republicans, to follow the most extreme voices in our base. And there is a danger that we will do that."

"The Investigation" is a podcast series offering an in-depth look at special counsel Robert Mueller's investigation into Russian interference in the 2016 presidential election and its aftermath, analyzing the potential fallout and political consequences. Hosted by ABC News correspondent Kyra Phillips and the ABC News investigative team, led by Senior Executive Producer Chris Vlasto. "The Investigation" is available for free on Apple Podcasts (via iPhone), Google Podcasts (via Android), Spotify (via smartphone and desktop), Stitcher (via smartphone and desktop), TuneIn (via smartphone and desktop), the ABC News app (via your smartphone) or your favorite podcast player.