MCKINNEY, Texas — Bill Mangieri of McKinney found that music has helped him through some difficult periods in his life. He strums his guitar in his room while talking with WFAA about his life of addiction.

"The music is really what has been keeping me going," he said. He was 13 when he first started smoking marijuana. That led to other drugs, but he tells WFAA that marijuana was his big problem. What started as an every weekend thing turned into 3 to 4 times a day. He says he was spending close $120 a week on marijuana.

Now Mangieri is one year sober after 3 years of chaos, but he faced the problems that most children face when dealing with addiction at a young age: returning to school. He knew that going back to school after rehab would put him in the same traps. He attended Serenity High in McKinney, a school for students dealing with addiction. "We show up everyday here to save lives. That's the bottom line," said Principal Stephen Issa.

The school is now located on the McKinney North campus. When WFAA arrived at the classroom, there were eight students sitting at desks listening to course material off their laptops.

In the 90s, North Texas was seeing the drug epidemic up-close. Plano was cast as the epicenter with more than a dozen cases of herion overdoses. "I mean people were dying. It was a very scary time for parents," said Lynn Sperry who was on the McKinney School Board at the time and still is. In 1996, she and her husband Bill were part of the group with the idea to start this school for students coming out of rehab.

For students like Mangieri, it made all the difference. This was his second chance to graduate and he did. The pace is different than a regular school. A strong majority graduate each year.

Serenity High is on a different schedule than McKinney North. The school starts 30 minutes later and ends 30 minutes earlier than North. When life is chaos, a little bit of serenity means everything. "They're worth fighting for. We know these kids," said Bill Sperry.