Bill & Ted are getting ready to climb aboard the school bus heading for an excellent school ski trip when Rufus drops in and asks if they would attend Be Excellent to Each Other Day in the future, but they decline, telling him about their ski trip. Before they can board the bus, however, a Bookmobile with flashing lights pulls up and they find themselves facing Sgt. Joe Donaldson of the library police. He informs Ted that he is the library's Most Wanted fugitive for not returning the library's copy of Little Red Riding Hood which he checked out when he was six, and that he now owes $35,000 in back library fines. Asking if they can at least make one phone call, they escape to their booth and decide to find the Grimm Brothers to obtain a copy of the book. They find the two authorities on grammar being evicted from their home for not paying their rent. Brother Jacob decides he might want to try his hand at writing folk tales, while Brother Wilhelm says it's silly. Bill & Ted realize they must stick with the brothers until they write their stories. They help the Brothers escape from the law and take them through time. Landing at Valley Forge, they end up getting to ski after all, running down George Washington. The Brothers Grimm are sent to the brig, Bill & Ted are made lieutenants, and Washington buys a portrait which Rufus was doing of him nearby (he buys the painting from Rufus for a dollar). Washington instructs Bill & Ted to come up with something for his last seven soldiers to eat, but isn't impressed with their snow cones and plain frosty slushes. The cold treats make Washington sneeze, causing an avalanche which clears a path and allows Martha Washington to be able to get through with some food, covered with snow (this inspires Jacob to think up Snow White and the Seven Soldiers). Bill & Ted and the Brothers Grimm manage to escape in their booth to Tennessee where they find themselves in a forest facing an angry bear. In their escape they run into Davy Crockett who says he's trying to track down their bear, which has taken off with their phone booth. Jacob starts thinking up stories about three bears living in a house. Rufus arrives to ask if they still want to attend the party with him, but when the bear shows up again they all beat a hasty retreat, only the bear and Davy Crockett manage to go along for the ride. They all end up in the future at Be Excellent to Each Other Day. Davy Crockett wrestles with the bear, which the Three Most Important People find outstanding entertainment. Bill, Ted and the Brothers Grimm go back to time traveling, and during their trip Brother Wilhelm gets so fed up with Jacob's idea for the Bear and the Three Most Important People he throws his brother's notes out of the booth and they have to stop to try to find the pages. During this stop, Bill & Ted spot a beautiful blonde riding a horse and follow her, ending up landing on her horse. She says she is Lady Godiva and says she shouldn't pick up hitchhikers, and since they have to go anyway they jump off her horse, inadvertently pulling her red cape off of her. Seeing the red cape, Jacob becomes inspired to write Little Red Riding Hooded Cape. Returning to San Dimas, Bill & Ted are taken to the head librarian, who is shocked when they hand her the original manuscript, which she says will pay off all Ted's fines. The librarian checks to see who the next Most Wanted fugitive is, and it turns out to be Bill, so after the dudes board the schoolbus for their ski weekend we see the Bookmobile chasing them out of town.
The misadventures of two time-travelling slackers as they travel into the distant past and future.
