The Watergate scandal centered on the Nixon administration's attempt to cover up a burglary of the Democratic National Committee headquarters at the Watergate office and apartment complex in Washing, D.C.
Nixon confined himself in a small and fiercely loyal group of advisors. They included: H.R. Haldeman (Chief of staff), John Ehrlichman (Chief domestic advisor), John N. Mitchell (Attorney General, and John W. Dean lll (Presidential counsel). They were all involved in Watergate.
At 2:30 AM, June 17 1972, a guard at the Watergate complex caught five men breaking into the campaign headquarters of the DNC.
The burglars planned to photograph documents outlining Democratic Party strategy and to place wiretaps on the office telephones. The group’s leader, James McCord, was also a former CIA agent. Three days after the burglary, H.R. Haldeman noted that Nixon had an obsession with how to respond to the break in.
September of 1972, The cover-up began quickly; Workers shredded all incriminating documents in Haldeman's office. The white house asked the CIA to urge the FBI to stop its investigations into the burglary on the grounds of national security. The CRP passed out nearly $450,000 to the Watergate burglars to buy their silence after they were indicated in
Nixon was reelected by a landslide over liberal Democrat George S. McGovern.
In January 1973, the trial of the Watergate burglars began.
March 20th of 1973, James McCord sent a letter to Sirica, in which he indicated that he had lied under oath. He also hinted that powerful members of the Nixon administration had been involved in the break in as well.
April 30th of 1973, Nixon dismissed white house counsel John Dean and announced the resignations of Haldeman, Ehrlichman, and attorney general Richard Kleindienst. Following this Nixon also went on TV and denied any attempt at a cover-up of the Watergate burglary.
In late June of 1973, John Dean admitted that Nixon had been deeply
involved in the cover-up of the Watergate burglary. The white house strongly denied Dean’s charges though.
In July of 1973, presidential aide Alexander Butterfield stunned the committee when he revealed that Nixon had taped virtually all his presidential conversations. A yearlong battle for the “Nixon Tapes” followed immediately after this.
In October of 1973, Archibald Cox took Nixon to court to obtain the tapes. Nixon refused and ordered attorney general Richardson to fire Archibald. This became known as the Saturday Night Massacre, Richardson refused the order and resigned. The deputy attorney gerneral also refused the order, and he was fired. Solicitor General Robert Bork finally fired Archibald.
Archibald's replacement was equally determined to get the tapes as well.
Days before the Saturday Night Massacre Vice President Spiro Agnew had resigned after it was revealed that he had accepted bribes from enginerring firsms while governor of Maryland.
Seven months after the "massacre," the house judiciary committee began examining the possibility of an impachment hearing.
In Spring of 1974, Nixon told he was relasing 1,254 pages of edited transcripts of White House voncersations about Watergate. Nixon's offering failed to satisfy investigators, who demanded the unedited tapes. Nixon refused, and the case went before the supreme court.
July 24, 1974, The court ruled unanimously that the president must surrender the tapes, they also rejected Nixon's arguement.

July 27, 1974, the committee approved three articles of impeachment, charging Nixon with obstruction of justice, abuse of power, and contempt of Congress for refusing to obey a congressional subpoena to release the tapes. Nixon resigned before the committee impeached him. His resignment was the climax of the scandal that led to the imprisonment of 25 government officials and caused the most serious constitutional crisis in the United States since the impeachedment of Andrew Johnson in 1868.

The Resignation of President Nixon.

works cited:
Gerald A. Danzer, J. Jorge Klor de Alva, Larry S. Krieger, Louis E. Wilson, and Nancy Woloch. The Americans: Reconstruction to the 21st century. Evanston, IL: McDougal Littell, 2007. Print.