The Brian Nichols who will graduate with honors from Manassas's Osbourn High School Saturday barely resembles the teenager whose defiance led him to drugs, stealing and the juvenile detention center.

Gone is the use of marijuana, PCP, cocaine and LSD, said Nichols, 17. Intact is a determination to mend and improve his life.

"I was my own boss, a master thief," said Nichols, who lives with his grandmother. "If you want something in life, you take it" was his code, he said. In the eighth grade, he began experimenting with marijuana. By the ninth grade, he was using LSD.

But over the past year,Nichols, with help from several school psychologists, changed.

"There are few students that have shown the initiative to seek the support and use it -- the way Brian has -- to get themselves going in the right direction," said Virginia Rutledge, an Osbourn school psychologist.

The secret, Nichols told a group of eighth-graders during a speech last week, is "You have to decide what you want for yourself . . . and you have to work for it."

When Nichols picks up his diploma this weekend, he will join about 2,900 seniors who will be graduating tomorrow, Saturday and Tuesday from eight high schools in Prince William, Manassas and Manassas Park.

Nichols's story is one of a broken family.

When Nichols was 10, his mother left him and his older sister with his grandmother Doris Stevens, 80. A younger brother, now 12, still lives with their mother in Ohio and another brother, now 10, was given up for adoption. His father left before Nichols was born.

"Brian was using drugs as a way as to cover up the years with his busted family and all," said Lawrence Stuart, Nichols's uncle and legal guardian.

In his freshman year, Nichols tracked down his father in Southern California. But a short stint living with him was difficult, so Nichols returned to Manassas to live with Stuart. But Stuart eventually kicked him out for skipping school and Nichols returned to his grandmother's house.

During his junior year, Nichols got involved in his heaviest drug use. "I just never knew what I was doing," he said.

Finally, his grandmother's heart attack last spring prompted him to evaluate what he was doing. "She just tripped me out. She was so old and I just thought if she died how I would feel," Nichols said. "I fell to the bottom of the pit. I had to do something to get out . . . to crawl back up the ladder."

It was hard. Nichols was arrested for yelling at an Osbourn teacher. He also was charged with breaking into the local animal shelter to free animals. But Nichols, who had started concentrating on his studies, managed to pass the year with a grade average barely above an F.

In and out of court all last summer, Nichols finally was ordered into a 56-day drug rehabilitation program in Culpeper, but was kicked out for being uncooperative. He then was committed to 21 days at Prince William County's Juvenile Detention Center.

"I had never been without the freedom to walk where I wanted to go," Nichols told the eighth-graders. Despite taunts from other youths that he was destined to return, Nichols vowed that he wouldn't. "It scared the crap out of me," he said.

Working with the chaplain at the detention center, Nichols said he began learning new values. "I actually started to feel good behind those cinder blocks."

In the early fall of last year, Nichols went back to court. And to his surprise, Osbourn Principal Marian B. Stephens testified on his behalf. He received a six-month suspended sentence and was released to the custody of Stuart.

Nichols said he quickly distanced himself from friends still involved with drugs and focused on his schoolwork. This spring he was honored as Osbourn's most improved student in English, math and science for this school year. He scored in the 97th percentile in math and science on the American College Testing program tests, according to Rutledge.

"I'm kind of glad it happened this way," Nichols said. "I'm glad I got over it. I guess it was a rite of passage for me."

Nichols, who recently purchased a 1957 Chevrolet truck for $700 and is working nights and weekends making pizzas, is preparing to go to Northern Virginia Community College this summer. After he saves some money, he wants to attend a four-year college.

Three years of bad grades and a drug record have severely narrowed his chances of receiving scholarship money or being able to participate in the Reserve Officers Training Corps.

But Nichols is optimistic. "I don't plan on going any place too extravagant -- maybe George Mason or George Washington," he said. "I'm not going for luxury, I'm going for an education."