Each family is directly involved in the busing crisis. The McGoffs are proud residents of Charlestown who see an attempt to change the dynamics of their school as an assault on their families. The Twymons have long endured sub-standard education and are hoping that busing will finally change this. Colin Diver, a Harvard Law School graduate and assistant to Mayor Kevin White, and his wife Joan Diver, director of The Hyams Foundation, move into the gentrifyingSouth End, a block from one of the Twymon sisters, who lives with her children in the shoddily constructed Methunion Manor housing project. The Divers are in favor of busing, but the effects hit home when they learn that it may result in their own son being bused to a foreign neighborhood. After six years of combating racial and class tension and street violence, the Divers leave the city for suburban Newton.
In addition to the family stories, Common Ground examines many of the issues related to busing, including the protest movements, the disaffection between the "two-toilet" Irish middle-class and their working-class brethren, the impact of busing on national politics, and the evolution of the city's newsmedia.
Robert Dentler, a sociologist who helped Judge Garrity draft the busing plan, criticized Common Ground for "distorted, questionable legends" and a "docudramatic method of reporting" that "cloak[ed] the ignorance, fear, and hostility of the minority of citizens in the white enclaves of Boston who initiated racial violence in the robe of civic innocence." 
Twymon - Rachel Twymon and her family, living in Orchard Park, respond to King's assassination; King's and Louis Farrakhan's ties to Boston
McGoff - Alice McGoff, living in Charlestown, responds to King's assassination; the political rise of John F. Kennedy and Ted Kennedy
Diver - Boston Mayor Kevin White and the city's elite respond to King's assassination; James Brown's concert in Boston calming racial tensions; Diver decides to work for White
Twymon - Genealogical history of Rachel Twymon; history of slavery and abolitionism in Boston
McGoff - Genealogical history of Alice McGoff; Irish immigration to Boston; history of Charlestown
Diver - Genealogical history of Joan McKechnie and Colin Diver; James A. Parker's 1963 housing discrimination lawsuit in Lexington
Twymon - Jonathan Kozol is fired from the Christopher Gibson School in Dorchester, where five of Rachel's children attend; the Coleman Report; Rachel's children attend parochial school, an East Boston junior high school, Boston English
McGoff - Ted Kennedy is pelted at City Hall by anti-busing protesters; Alice McGoff becomes an anti-busing activist in ROAR
Twymon - Rachel Twymon's daughters Cassandra and Rachel are bused to Charlestown schools; anti-busing protests at Charlestown High School
McGoff - Alice McGoff's children at Charlestown High participate in anti-busing protest; they witness The Soiling of Old Glory incident
Diver - busing plan threatens the experimental Bancroft School in the South End; Boston philanthropy; Joan rises to become director of the Hyams Foundation; anti-busing activists protest the United Way of Massachusetts
McGoff - the McGoffs, the Catholic Church, and the busing crisis
Twymon - fiscal problems of Union United Methodist and Methunion Manor; Rachel Twymon's disciplinary problems with her children; street crime
Diver - gentrification conflicts in the South End; street crime directly affects the Divers
McGoff - riot police enforce busing in Charlestown; Tip O'Neill opposes anti-busing amendment; anti-busing protesters dwindle as splits emerge on class lines
The Editor - Boston Globe Editor Tom Winship; the Globe responds to civil rights movement, changing demographics, busing crisis
Twymon - Rachel Twymon's sister Alva Walker Debnam buys a home in Dorchester; family undergoes a racist siege of violence and intimidation; United States Bicentennial; race riot that day centered around Debnams leads to Tommy Walker seriously injuring three rioters
McGoff - Lisa McGoff, Alice's daughter, becomes Charlestown High's senior class president
Twymon - Rachel's son Freddie is convicted of rape; conflict between Rachel and her family; successes in the Twymon household
The Mayor - Kevin White almost becomes George McGovern's vice presidential candidate; White's rise to power; detente with Hicks; conflict with Garrity; "retreat from the tough issues"
Diver - ongoing street violence and ineffective response; decline of the Bancroft; Divers move to Newton