Houston ? Andrew Fastow, chief architect of the shady, off-the-books deals that brought down Enron, pleaded guilty along with his wife Wednesday in an agreement that could take prosecutors to the top of the corporate ladder at the scandal-ridden company.

The plea bargains represent the biggest breakthrough yet in the two-year investigation into a scandal that led to the energy giant’s collapse and rocked Wall Street and Washington alike.

Fastow, Enron’s former finance chief, agreed to a 10-year prison sentence that will make him the highest-ranking executive to do time in the case. He also agreed to forfeit $23.8 million and help the government build a case against the executives who once occupied Enron’s most opulent top-floor office suites: former chairman Kenneth Lay and former CEO Jeffrey Skilling.

“I and other members of Enron senior management fraudulently manipulated Enron’s publicly reported financial results,” Fastow, 42, said in a statement filed with the plea agreement, adding that the purpose was to mislead investors and inflate the company’s stock price and credit rating. He did not read the statement in court.

Fastow’s wife, Lea, pleaded guilty to filing false tax returns related to Enron’s ill-gotten gains. Lea Fastow, also 42, was Enron’s assistant treasurer.

Without a plea, Andrew Fastow would have gone to trial on 98 counts of fraud, money laundering, insider trading and other charges.

Prosecutors say Fastow masterminded a sea of partnerships and tangled financing deals that hid Enron debt and inflated company profits while funneling millions of dollars to him, his family and selected friends. The partnerships had names like LJM (the first initials of Fastow’s wife and two sons) and Chewco (after the “Star Wars” character Chewbacca).

Fastow pleaded guilty to two counts of conspiracy to commit fraud — one covering the LJM partnership, the other involving transactions that he used to pocket an estimated $45 million.

“I also engaged in schemes to enrich myself and others at the expense of Enron’s shareholders and in violation of my duty of honest services to those shareholders,” Fastow said.

Lea Fastow’s deal calls for a five-month prison sentence and a year of supervised release, including five months of house arrest. But U.S. District Judge David Hittner will decide later whether to accept the sentencing deal. Lea Fastow still has the right to withdraw the plea.

Former Enron finance chief Andrew S. Fastow, left, and his wife, Lea, center, leave the federal courthouse with Lea's father, Jack Weingarten, in Houston. The Fastows both accepted plea bargains and pleaded guilty in court Wednesday.