The school bell peals. Doors fling open and a thousand teenagers spill into the halls.
"You know the rules, people, " a man bellows through a bullhorn. "No headphones. No hats. Get your ID badges out and get moving!"
Students have six minutes to crisscross the sprawling two-block campus. When the bell rings a second time, classroom doors shut and the halls are strangely quiet.
Loitering is not an option.
There's too much at stake.
Miami Central -- a high school historically beset by chronic truancy, declining enrollment, dispirited staff and general disrepair -- is fighting to avoid a grim distinction. It could become the first school in the state to face a federally mandated overhaul because of repeated failures on the Florida Comprehensive Assessment Test.
Over the past five years, the school has received five consecutive F grades. One more, and Superintendent Alberto Carvalho will be forced to make radical changes under a new federal mandate.
That could mean stripping the curriculum down to its bare bones -- cutting art, music and electives -- and replacing dozens of teachers and administrators, including the principal.
Carvalho could even shut down the 50-year-old school.
Enter Doug Rodriguez, the state's No. 1 principal, now at the helm of the school with the state's worst academic record.
Rodriguez, a 20-year veteran of the school system, left a coveted job at a top high school on a mission to shake things up at Central.
In a two-month flurry, he cleaned up the halls, shipped dozens of troubled students to alternative schools, designated a dean of discipline, appointed as many as four teachers to the same classroom and boosted morale.
And when The Miami Herald sought to chronicle Central's efforts to meet the challenge, Rodriguez and Carvalho agreed, giving a reporter and photographers unfettered access.
"Things are changing around here, " said Shelby LaBeach, 18, a senior who is Miss Miami Central, the official student ambassador. "We have our own Obama."
Miami Central Senior stands on Rocket Boulevard, a stretch of Northwest 95th Street in West Little River named for the school mascot.
The school's 1,600 students come from a hodgepodge of neighborhoods, including Opa-locka, Miami Shores, North Miami and El Portal.
More than half are from low-income families. About 14 percent are enrolled in special-education programs.
The students take pride in their marching band and turn out en masse for football games -- especially when the Rockets play the rival Northwestern Bulls.
But administrators have had difficulty controlling gang activity and violence in the halls. During the 2005-06 school year, more than 1,100 students received in-school suspensions. The following year, only a third of Central students said they felt safe at school, according to a district survey.
"Kids were bringing the streets into school, " said André Young, 17, a senior and the drum major in Central's marching band.
Central also struggled academically. Last year, 10 percent of sophomores passed the reading portion of the FCAT, compared with about 30 percent districtwide and 38 percent statewide.
Hundreds of students opted to leave, taking advantage of a state program that allows transfers out of low-performing schools to other public schools.
A decade ago, former Gov. Jeb Bush unveiled his A+ Plan for Education as a way to bring accountability to struggling schools like Central.
Many, however, did not improve, prompting state education officials to approve what is seen as a nuclear option: shutting down persistently failing schools.
The threat turned out to be hollow. Communities protested whenever there was a threat to close the local school. And the option rarely made financial sense for school districts.
But other solutions -- like replacing teachers and moving freshmen to a separate campus -- have also been unsuccessful.
Last fall, the federal government identified Central as one of five South Florida schools that must make a dramatic improvement on this spring's FCATs.
The others: Edison Senior High, Holmes Elementary and Liberty City Elementary, all in Miami, and Larkdale Elementary in Fort Lauderdale.
Carvalho, the superintendent, has pledged not to close any of the Miami-Dade schools. But he says he will implement unprecedented reforms at any county school that fails to make the grade.
Rodriguez is the first to admit that turning Central around before the end of the school year won't be easy.
"The No. 1 thing we have working against us is time, " he said.
The state tests in writing have already come and gone. And the tests in reading, math and science begin this week.
A NEW BEGINNING
Rodriguez, 43, started at Central on Dec. 16 -- just three days before the holiday recess and six weeks before the writing FCAT.
"It was overwhelming, " Rodriguez said. "But I understood very quickly what needed to be done."
The first step, he said, was to establish control.
Central had long had a problem with students hanging out instead of going to class. At Rodriguez's request, school aides began to do hall sweeps. Anyone who was not in a classroom by the late bell was brought to a detention-like class called "lockout."
Forty students with multiple suspensions were transferred to alternative-education centers, Rodriguez said.
Discipline has now become part of the culture at Central.
Each morning, administrator Daryl Grice, the school's "dean of discipline, " reminds students over the public-address system of what is expected of them: "You've got to be on time and respectful to your classmates and teachers."
Now, many students shake hands with their teachers as they pass them in the hallways.
"We used to break up fights in the halls at 6:30 a.m., " said veteran security guard Dell Gibbs. "Now we have kids wearing their IDs."
Rodriguez has also brought a new focus on academics.
The principal pored over students' test scores. Then he added a second, third or fourth teacher to some classrooms.
He also brought in teachers for the teachers. Many began to give up their lunch or planning periods to attend seminars on teaching strategies.
But perhaps most important, Rodriguez says he worked to make the Central community believe in itself.
For years, students and teachers had struggled to overcome the stigma that comes with being a chronically failing inner-city school.
"People think of Central and they think of a bad school with bad kids, " said Nicole Louis, 17, the senior-class president. "They don't look any deeper."
Rodriguez, students say, pays attention to them.
The principal spends most of the school day walking up and down the halls, popping into classrooms at random.
With each visit, he reminds students of what they are capable.
On a recent Friday morning, Rodriguez visited a 10th-grade language arts classroom. Earlier in the week, he had promised to write an original poem for the students, who were studying poetry.
The teenagers listened intently as the principal read his work.
"Now I see you with me and now I see the success in you
"You Rockets are what moves me
"You Rockets are what makes me believe."
The students cheered.
"That was awesome, " sophomore Djenane Joseph said to a friend.
"You guys can do this, " Rodriguez told them. "You've all been working hard. You can make gains."
Rodriguez arrives at school at 5:30 a.m. -- and stays until 5:30 p.m.
Throughout the morning, he brews several pots of coffee and invites employees to drop by.
When the students start to trickle in, Rodriguez welcomes them at the main entrance.
"How are you ladies feeling this morning?" he asked a group of teenage girls last week. "Ready to learn?"
For Rodriguez, this is more than just business.
He has a personal connection to the school.
Rodriguez came to Central as a rookie teacher in 1988. He had interviewed for a teaching position at the school the day after his graduation from Barry University.
Karen Potter, the indoor suspension coordinator at Central, said the young social-studies teacher was a powerful force.
"The kids were practically drooling to learn, " she recalled. "They wanted to be in his class."
After three years at Central, Rodriguez moved around to several other schools in the district.
He soon became a top principal.
Rodriguez was instrumental in helping Miami Springs Senior High rise from a D to a B in just two years.
In 2006, Rodriguez became the first principal at Ronald W. Reagan Senior High, a new school in middle-class Doral.
In its first year, Reagan was the only non-magnet high school in Miami-Dade to receive an A from the state. It earned an A the following year, too.
Rodriguez was named Florida's Principal of the Year last fall.
He decided he was ready for a new test.
"I probably could have stayed at Reagan for the rest of my career, " Rodriguez said. "It was a great school, but I like to be challenged."
Last November, Rodriguez asked for a meeting with Carvalho, the district superintendent.
One month later, when the principal at Central took a medical leave, Carvalho put Rodriguez in charge.
Placing Rodriguez, who is of Cuban descent, in a predominantly black school was a risky move. Before Rodriguez, five of the last six principals at Central were black. District officials worried about how the community would respond.
But leaders, teachers and staff members welcomed Rodriguez back to Central.
"We got exactly what I had been praying for, " said Kenneth Hall, who has known Rodriguez since the two were rookie teachers.
Already, the changes are apparent.
The hallways are cleaner. Candy wrappers and potato-chip bags no longer line the floors. There is little graffiti on the walls.
Longtime student activities director Bessie Legrant said she noticed the change when more teachers turned in surveys about the school from the district.
"One teacher said to me, 'This is the first time I've ever finished this, and I feel good about it, ' " Legrant said.
Teachers say attendance has improved dramatically.
The same goes for students. Senior Leonard Dumercy, 17, said he and his friends no longer skip class.
"There's a new attitude, " he said. "Mr. Rodriguez helped us focus."
Rodriguez also made the school feel safe again, said Potter, the veteran indoor suspension coordinator, noting that there are far fewer fights in the hallways.
That isn't to say there aren't any hotheads left at Central. But a majority of students are focused on the task at hand: improvement on the FCAT.
Many say they feel more confident about their abilities. And they feel good about Central's future.
"We know we can be a B school, " said Alonzo Faison, 16, a freshman football player. "We won't settle for anything less."