Mason's Journal belonged to Mason Lockwood. He wrote about everything since he killed Jimmy and became a werewolf. In The Sacrifice, Tyler and Caroline found it in the old Lockwood cellar where Mason planned to transform the full moon prior to Tyler's first transformation as a werewolf. In the diary, they found a SIM card with Mason's first transformation videotaped from the very beginning.
- August 31st,
My body is changing. I'm edgy, I'm angry, impatient. I get so mad, I black out and forget what I say or do. I'm not myself, not since Jimmy's death. What's happening to me?
- September 16th,
I chose the garage. I could deadbolt the door. It was far from the street so no one could hear. I bolted hooks to the floor for the carabineers. I diluted wolfsbane with water to weaken myself, but I could barely get it down without puking. It felt like I was drinking battery acid. Hours passed and nothing happened. It got so quiet, I could hear my own blood pumping. That's when...I kept thinking I'd black out and not feel it. But I did. I... I felt all of it. Unimaginable pain. I thought it would never end. It was the worst night of my life.