Dan's Lost Journal

One day, while Dan and Phil are rummaging through some boxes, they find Dan's journal from around three years back. Dan completely forgets what he has written, and he decides that they can take a look through it, and maybe even film it for YouTube. They put it to the side, and begin to look through more boxes. When it comes the time to read his journal, they sit on Dan's bed, and silently turn the camera on. As normal, they do their introduction and begin to read his journal. Everything is fine, until it comes to the fourth page. Dan quickly hides the journal and decides it's a good time to end the video. What secret could Dan possibly be hiding from Phil, and will he ever find out what Dan had written in that journal?