Marty switches places with Marty Jr. and refuses Griff's offer, but Griff goads Marty into a fight, and a subsequent hoverboard chase ensues. Griff and his gang are arrested, saving Marty's future children. Before rejoining Doc, Marty purchases an almanac containing the results of major sporting events from 1950 to 2000. Doc discovers it and warns Marty about profiting from time travel. Before Doc can adequately dispose of it, they are interrupted by the police, who have found Jennifer incapacitated and are taking her to her 2015 home. They pursue, as does the elderly Biff, who has overheard their conversation and retrieved the discarded almanac.