Plymouth Police have begun a search for a bomb in the high school.
The school website says they received a threat Wednesday afternoon, written on a bathroom wall. It said a bomb would go off at 12:30 Thursday in the school library.
The school is on a 2-hour delay Thursday as State Police arrive to search the school. No one is allowed inside until they say it is safe.
Police will remain in the building throughout the day to monitor threats.
Check back with NewsCenter 16 for updates.