Purple Tentacle, one of crazy Dr. Fred's creations, drinks contaminated water from Dr. Fred's Sludge'o'matic, mutates into an insane genius and grows arms, and now he's plotting to take over the world. In an effort to stop him, Dr. Fred sends the three insane friends, Bernard, Hoggie and Lavern back in time to yesterday, in order for them to turn off the Sludge'o'matic and stop the sludge from spilling into the river. Naturally, the cheap doctor uses a fake diamond over a real one in his time machine, which blows up sending Hoggie 200 years into the past and Lavern 200 years into the future.