The story begins with three young riding enthusiasts' adventure - they were pretty confident that they could complete a 38-mile mountainous trip in 5 hours. Unexpectedly, they had been riding uphill in the shade of the mountain all day. As the night grew darker, they were feeling cold and exhausted. For the final 16 miles, they could no longer ride and had to push their bikes up the mountain against the wind. Carl said, "If only we had bikes with electricity to give us a ride." The three young people couldn't stop talking about it and they had a great time. They decided to upgrade their gear and challenge themselves one more time. Unfortunately, this project was halted due to the hefty expenses.