Mordecai and Rigby are digging a hole so they can put a new sprinkler system in. While they are digging, they come across a big metal box. They dig it out and look at it. Thay opened its door and looked inside. There were over a million tiny buttons that all had different years on them. Mordecai and Rigby took it inside and showed it to Benson. Benson said, "Do not use this. It is a time machine. It's very dangerous. That is why my father burried it." Benson tells them a story about the time machine.Benson told them to throw it away, but they didn't want to. So they stuck it under Mordecai's bed. Later Mordecai and Rigby get into the time machine and press the button that says 64. They get brought to a jungle. Suddenly a T-Rex jups out and starts chasing them. They run back in to the time machine. They press the button that says 2012. Nothing happens. They figure out that to get back to the original year they needed a key so they have to go through time looking for the key.So throughout looking for the key they must climb mountains. Fight dinosaurs. Befriend cavemen, and learn to speak seven different languages.When they get the key they turn it and it brings them back to 2012. But when they get back everything is wiped out. They knew they must have done something while traveling through time. Mordecai says, "Dude... we have to go back." The screen blacks out and says, "To be continued..."

This episode will premiere on November 15th and it will be the season finale of season 3. Part to will be the season 4 premiere on January 6th.