10:00 a.m.
The principal of Opportunity, Alabama's high school finishes her speech, welcoming the entire student body to a new semester and encouraging them to excel and achieve.

10:02 a.m.
The students get up to leave the auditorium for their next class.

10:03
The auditorium doors won't open.

10:05
Someone starts shooting.

Told over the span of 54 harrowing minutes from four different perspectives, terror reigns as one student's calculated revenge turns into the ultimate game of survival.