Barney and the scientist were alone on and island. After the scientist fired his assistant Tayloe.
Barney was a very smart rat. He could read books.
One day when the scientist let Barney run around for a bit. Then barney stole his key went out the door and threw it down the well.
The scientist went to go retrieve the key. But once he was at the bottom his flashlight gave out. So he went back up. Once he was close to the top he heard Barney making noises. He thought he was trying to warn him because they rope was severed.
Barney wrote in the scientist's journal saying how he died and the scientist would be dead soon too. Because Barney killed the scientist by trapping him in the well.