You will return home by foot
During a bike tour you always carry the basics, a multitool, a pump and few parts. Some damages are imposible to be repaired on the mountain, either because you do not have the tools and the spare parts or you do not have the knowledge (eg damaged tire, broken wheel or crankset etc.) If you are lucky and you see a pasing car, do hitchhiking, if the road is passable and you have a mobile, call someone to pick you up. If nothing of these happens, then walk.